Great pics of fantastic gear and music library!

bdp24 October 16, 2018 00:58

Man, that is one serious compressor!

bdp24 March 17, 2018 09:05

Oh, I forgot to mention.....that 1 ohm impedance of the Quad 57 at very high frequencies is more of a problem in the load it presents to the amp, rather than in affecting frequency response, I believe. The impedance, plus it's phase angle (this is approaching the limits of my knowledge, but I won't let that stop me ;-), drives some amplifier circuits into instability, causing them to "ring". Not any Music Reference amps, though.

bdp24 November 21, 2015 16:13

Chris, I've heard the ET 8a's, at Brooks Berdan's shop. The change in the b version was to the tweeter and it's cross-over only, which is at the unusually high frequency of 10kHz! The x/o is 1st order (6dB/octave), so there is a lot of overlap between the tweeter strip and the main panel (275Hz-10kHz). One of the great things about the LFT is it's main panel reproducing such a large portion of the sound of music, without a x/o in the 275Hz-10kHz range. Brooks had been an ET dealer for years (selling a lot of the arm, and installing it on Oracle and VPI tables), and considered the ET LFT version (dual-sided magnet structure/push-pull operation, lower moving-mass Mylar drivers, etc.) of the magnetic-planar design superior to Magnepan's. I was an ESL-only kind of guy for years (Brooks admired them too, selling the current Quads), only recently adding the ET's to my system. At only $2500/pr, an excellent value!

bdp24 November 21, 2015 16:01

I have a pair of grills for the 57's made by Crosby, the guy known for his Quad 63 mod. It just has a more open "weave" than stock, and I play my 57's with the back grill and burlap & felt removed. My stacked frames have MDF grill frames with cloth stretched across them, covering the naked 57 panels. VERY dangerous voltages inside the 57's!

I at one time also owned a pair of Braun 57's! Peter Walker licensed Braun to make their own version of the 57 for the German market, with the Quad guts in a Braun designed frame. The frame was light gray painted aluminum about 6" deep, that wrapped around the panels, rounded at the four corners like Braun's bookshelf speakers, with integral tubular stands that raised them off the floor. The panels of my pair were shot, and I didn't want to restore another pair, so I sold them to Brooks Berdan for his Hi-Fi museum. I haven't seen them since he died.

bdp24 November 19, 2015 03:00

I have a pair of grills for the 57's made by Crosby, the guy known for his Quad 63 mod. It just has a more open "weave" than stock, and I play my 57's with the back grill and burlap & felt removed. My stacked frames have MDF grill frames with cloth stretched across them, covering the naked 57 panels. VERY dangerous voltages inside the 57's!

I at one time also owned a pair of Braun 57's! Peter Walker licensed Braun to make their own version of the 57 for the German market, with the Quad guts in a Braun designed frame. The frame was light gray painted aluminum about 6" deep, that wrapped around the panels, rounded at the four corners like Braun's bookshelf speakers, with integral tubular stands that raised them off the floor. The panels of my pair were shot, and I didn't want to restore another pair, so I sold them to Brooks Berdan for his Hi-Fi museum. I haven't seen them since he died.

bdp24 November 19, 2015 03:00

Chris, Roger is very serious about making his amps load tolerant. He does not approve of the high output impedance of many (most?) tube amps, as they interact with the speaker's often falling impedance at high frequencies (the Quad 57's impedance falls to around one ohm up there!), the pairing of which results in a rolled off high end. I didn't ask Roger, but I'll bet he worked on the RM-10 until it could provide a flat frequency response when driving the Quad. Solid State amps have very low output impedances of course, but for whatever reason aren't usually a good match with the old Quads, the Bedini 25/25 and small Class-A Levinson's being notable exceptions.

There is a new add-on tweeter that may be great with the Quad---the Townshend Audio Maximum Supertweeter. It's gotten great reviews in Britain.

bdp24 November 16, 2015 12:08

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Chris, my bdp24 name comes from my favorite drumset finish and bass drum size, Black Diamond Pearl and 24". I started using it when selling vintage drums (1920's-early 70's) on ebay in the late 90's (964 feedbacks, 100% positive!), and have used it ever since.

I had a woodworker friend of mine (Pete Curry, currently playing bass in the instrumental band Los Straitjackets---we played together in The Hillbilly Soul Surfers in the 90's) make me a pair of stands for stacking Quads, three glued-together layers of 3/4" MDF (2-1/4" thick!) on either side of each pair of panels. I looked at all the different stacking ideas and stands, and came up with my own version. I put the bottom pair raised up so the middle of the panel was 36" off the floor, with the upper panel right above the bottom, almost touching. That way a seated listener would not be looking "down" on the performance (I don't like the balcony perspective either), and a standing listener would hear the upper pair pretty much as the seated listener heard the bottom pair. I made the stands almost 8 feet tall (they are VERY heavy), putting spikes on top (to anchor the stands to the ceiling!) as well as on the bottom. I don't stack anymore, preferring a single on the old Arcici stand.

Almost all 57's need to be reconditioned/repaired, including mine. I bought three pair locally, and took them all to John Koval in Orange, California. John made a name for himself in the 80's when he designed a mod for the 57, which was pretty popular amongst non-purist Quad owners. Many found the very top of the speaker lacking (including Mark Levinson, who added a Decca tweeter to the stacked panels in his HDQ loudspeaker), so John did some measuring (he was an old-school EE type). He attributed the falling response to the narrow strip in the middle of the tweeter panel. Everyone thinks the 57 is a two-way design, but it's not, it's a three way. The highest frequencies emanate from only the very center of the tweeter panel, which because of it's smaller radiating surface doesn't provide as much output as the rest of the tweeter panel does for the lower highs. So John altered the x/o, boosting the output of the ultra-highs, which elevates and extends the high end of the speaker. He didn't tell me that, and he potted his mod in resin so no one could figure it out, but I deduced all of this from what he said to me during our conversations and from what he wrote in his literature.

I don't have the A-S M60's anymore, and the Quads are packed away for now. In fact, everything is box up, as I'm moving up to Portland Oregon in a few weeks. I'm hoping to find a place with a big enough room that I can have all my panels set up (the ET LFT-8b's, Quads, and Tympani IV's), along with the OB and sealed subs. Or at least big enough that I can put the ones not in use against a wall (Ivor be damned!), and alternate between them. I'll have to take pics after I'm up and running, and post them. I've never taken pics of my stuff, as I've been kind of an isolated audiophile (VERY few musicians share my interest in Hi-Fi, listening through and to absolute garbage), connected to the community only through print mags and dealers (Brooks Berdan, primarily) until fairly recently. I am not happy I only learned of Audiogon about a year ago !

The RM-10 is cheap enough (a couple have sold here in the past year for around $1500, iirc) that I may get one for the Quads. It's definitely THE amp for them. I listen to a lot of music with vocals, and the Quads are still unequalled at reproducing them. Baroque is my most listened to Classical, also well served by Quads. But they just don't cut it with AC/DC, at least not for long!

Your good results with nearfield subs has me interested in trying it myself Chris. I'm going to put the OB's by the speakers and the sealed Rythmiks by the listening position. I'll let you know how it works for me!---Eric.

bdp24 November 10, 2015 09:39

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Let me address your concerns Chris, all well founded.

- Yes, the OB/Dipole sub needs to be away from the wall behind it, as do all Dipoles, including Quads. They can be right up against a side wall though, or on the floor if placed horizontally.

- B & W DM70! Now there's a speaker I haven't thought of in years. In '71 I heard my first ESL's, the Infinity Servo-Static 1. I also heard two speakers with ESL tweeters, the Infinity 2000A and ESS Tran-Static I. Thus began my love affair with ESL's, which continues to this day.

Having heard those speakers, I started planning the purchase of my first perfectionist system. By the time I had the dough, Audio Research and Magnepan had made it to the West Coast. I happened to make my first visit to the new ARC dealer in my area (Audio Arts in Livermore, CA, owned by Walter Davies, now the maker and seller of the excellent Last LP care products) on the day that Bill Johnson was delivering and setting up his complete ARC system, including bi-amped (with D-51 and D-75 amps) Magneplanar Tympani I-U loudspeakers. Over the next few months I went to listen to the Maggies at the shop, wherein Walt had a pair of the DM70's as well. I bought the Tympani's (and the ARC electronics), but remember the B & W's well. To be honest, I can't imagine why you would be using the woofer in that speaker as a sub for Quads! Let me tell ya, you are in for a pleasant surprise when you hear the OB/Dipole sub (or a Rythmik)!

- Danny Richie has found a pair of the OB/Dipole subs to produce about the same output as one of the sealed F12's. So yes, you are giving up 3dB by going OB/Dipole. Then why do people do it? I have both a pair of GR Research OB/Dipole subs and a pair of Rythmik F15HP subs, and though they have much in common, there are also differences. You will find all of the following on the GR Research AudioCircle Forum, but it is buried in a lot of other information. So let me condense it for you:

Danny Richie is a loudspeaker designer specializing in Open Baffle design, selling his designs as kits to the DIY crowd. Guys who make not only their own speakers, but often their own electronics as well. His designs are mostly of high-sensitivity, and his customers are into low-powered SET tube and Class A SS amps to power Danny's speakers, the Pass DIY designs being very popular. Danny is a firm believer in high-quality passive parts, offering x/o upgrades to commercial loudspeakers using them. So Danny is coming from a perfectionist, no compromise, high performance point of view.

He had been a long-time fan of not just OB speakers, but OB subs as well. OB subs are not new, and are favored by some, Danny included, for their non-room loading nature (a result of their Dipole design), and clean unboomy character (no enclosure!). He learned of a subwoofer designer, conveniently also located in Texas, who had a new idea that he had patented, which he had named Direct Servo Feedback. The designer's name was Brian Ding and his company Rythmik Audio, and Danny got in touch with him. Danny's creative mind envisioned that an Open Baffle sub combined with Brian's DSF design could produce a new standard in bass reproduction. The two put their heads together, and we can now enjoy the fruits of their skills and labors.

But here's what you have to realize: Though the OB/Dipole sub uses the Rythmik plate including the Direct Servo Feedback circuit that controls the 12" woofers in the sub, the sub is a Danny Richie design. Enrico is of course not going to recommend the sub to you (or even mention it), or be able to advise you on it's use. He is involved with Rythmik, a completely separate operation with a different target audience and customer bass (largely Home Theater, most definitely not audiophile. Most Rythmik customers power their mass-market speakers with receivers, like Denon). Brian Ding himself is not really that much enamored with the OB sub. Upon hearing it, he admitted to not quite knowing what to make of it, finding it to sound very "lean". Now, the Rythmik subs themselves have been described as sounding lean when compared to "normal" subs, even very famous, expensive, "Class A" rated ones. Compared to them, a Rythmik is superior in degree, but not in kind. The OB/Dipole sub is different in kind, as different from a Rythmik sub as a Rythmik is from all the thick/heavy/boomy subs everyone has heard and found unacceptable for use with panel speakers. The same way that an electrostatic loudspeaker or any other dipole is different from Any and all box speakers.

The GR Research OB/Dipole sub does not sound like a sub. When added to a high-transparency speaker, it does not expose it's presence, but rather blends invisibly. You do not hear it as a separate entity, but only hear the bottom octave of music evaporate when you turn it off! It makes your speaker sound like the bottom octave of missing sound has been restored, not that a sub has been tacked on the bottom of the speaker, trailing along behind the music like a caboose. Now I ask you, is that worth giving up 3dB for?!

- The Rythmik plate amp is loaded with controls that will allow you to add the sub to your Quads without giving up any of their sound quality. If you want to x/o at 80Hz using a 2nd order x/o you can. If you prefer 120Hz with a 4th order, you can do that as well. Or any combination of the two. You can locate the subs anywhere you want, as the plate amp's continuously variable 0-180 degree phase knob simulates physical distance, and can get the speaker and sub in phase at the x/o frequency no matter where each is located.

- There is actually one person making speakers that include the OB/Dipole woofer system, Ric Schultz at Electronic Visionary Systems. He has been making Open Baffle speakers on 2-1/4" thick MDF panels, using the GR Research 12" woofers and Rythmik DSF plate amp for the bass section. The midrange an tweeters he was using (BG Neo) are currently unavailable, but Ric may be willing to make you a pair of subs. He does not, however, make it as a W- or H-frame, but as a flat baffle. So there may be more low-end cancellation and roll-off in his version of the sub. You can check him out on his website.

- Here's my experience with the Music Reference RM-10: Roger Modjeski gave a seminar in the early 90's at Brooks Berdan's shop in Monrovia, CA. In it, Roger discussed a new design he was still working on, which became the RM-10. He mentioned that the Quad was one speaker he had been using in fine-tuning the circuit. After the talk I approached Roger, telling him I was looking for amplification for my stacked Quads. I asked him if he advised me to wait for the RM-10's design to be finalized and put into production, when I could get a pair of them, one for each pair of Quads, or to get one of the already available RM9 amps. He told me that because he was a believer in high-overload margins, he would go with the RM9. I pressed him further, pointing out that one RM-10 would have more power than a pair of Quads would be able to accept without damage to the panels from arcing, that the combined insanely low impedance of the Quads at high frequencies was even lower in a stacked pair, and that lower-powered amps, all else being equal, usually sound better than higher-powered ones. That didn't persuade him.

A couple of years later, Roger gave another seminar at Brooks shop (Brooks loved Rogers stuff, selling it as his "reasonably" priced tube line, selling VTL to his wealthy customers). When Roger saw me, he came over and said my questions had lead him to reconsider his position on the choice, having seen the wisdom in my thoughts on the subject. Yes, he did now recommend a pair of RM-10's. Unfortunately, I had already bought an Atma-Sphere M60!

Well Chris, I hope I haven't overstayed my welcome, and that at least some of this rant will be of use (or at least interest!) to you---Eric.

bdp24 November 08, 2015 09:33

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Oh, I neglected to address your desire to fill in only the bottom of the Quad, without encroaching on the it's sound above that. A well-justified concern Chris, and the inability of almost all subs to do just that is exactly why most Quad lovers choose to just live without deep bass, the loss of too much of the Quad's sound being too high a price to pay to get it.

If you read comments on the Rythmik AVS Forum from some of the non-audiophile/more-home theater customers who have bought Rythmik subs after having owned mass-market ones, they are at first concerned that they don't hear their new Rythmik sub as much as they did their old one. After living with it for awhile, they learn that the sub sound they were used to is the thick/slow/boomy sound that characterizes many subs, the kind of bass that makes most subs unacceptable for use with really good speakers, like Quads.

Even the non-OB/Dipole Rythmik is very transparent and non-obtrusively invisible, producing bass that sounds not separate and detached from the speakers, but merely making the speakers sound as if they themselves have gained an octave (or more---many speakers are already in serious decline at 42Hz, the frequency produced by the E string of the 4-string bass played open/unfretted) of bandwidth at the bottom, providing the bass foundation necessary for some music to sound really "right". I used my Quads un-augmented for years (for awhile in stacked pairs for which I made 2-1/4" thick MDF stands, spiked to the floor AND ceiling!), but can't imagine them now without the GR Research OB/Dipole subs. They're THAT good! The subwoofer (and the bass section of the GR Research Super-V, a Danny Richie loudspeaker incorporating the sub) was voted "Best Bass at the Show" at RMAF for quite a few years running. If one of the major loudspeaker/subwoofer companies licensed the rights to manufacture and market the sub, I have no doubt they would sell a LOT of them. Until then, one has to DIY.

bdp24 November 06, 2015 08:50

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Yeah Chris (saw your name!), Brian Ding of Rythmik designed and builds the plate amp (some of the electronics are sent to him from China, of course), and worked with Danny of GR Research in the design of the two OB woofers (8" & 12"). They also worked together in the development of the shelving circuit (6dB/octave boost below a certain frequency, to counteract the front-to-back cancellation inherent in all dipole speakers and subs) installed in the amp when it is used for driving the OB woofers. But Rythmik (Brian and Enrico) doesn't actively promote the OB/Dipole sub, Danny Richie of GR Research does. Any questions you have about the sub are better asked of him---it is his "baby". And it is his customers who buy, use, and discuss the OB/Dipole sub, not Rythmik customers. It's an unusual relationship and arrangement Brian and Danny have, but has worked out great. Both happen to be located in Texas, which may be one reason they got together.

I don't know how you feel about this idea Chris, but the width of a W- or H-frame is around 16". The OB/Dipole sub can actually be used horizontally (laid on it's side), and a Quad speaker set on top of it, the sub thus becoming a 16" high stand for the speaker. Since there is a null on each side of the frame, there is no sonic penalty for doing so, except for any vibration transferred from the sub frame to the Quad. A set of Townshend Audio Seismic Pods between sub and speaker will take care of that. The Gradient OB/Dipole sub for the Quad 63 speaker was used that exact way, Gradient even styling the sub to look like it came from the Quad factory, it's size and shape matched to that of the 63. A simple phase-coherent 6dB/octave crossover (just a capacitor and resistor across the input jacks of the amp powering the Quads) can then be used, as the woofers and ESL panels will be closely aligned.

Richard Vandersteen's sub itself uses a 1st order crossover, and has been very successfully used with Quads and other planars. Brooks Berdan was a big fan of them when he was a Vandersteen dealer (one of the biggest in the country), and I heard them at his shop many times. I could live with a pair, and they would definitely be worth a try, especially if you don't want to have to go to the trouble of building or having built for you the frames for GR subs.

The Gradient OB/Dipole sub for the Quad 63 was reviewed in TAS in the early 90's, I believe it was. You can read the review at regonaudio.com, in which the advantages and benefits of it's use with the 63's is discussed. And there is a lot to read about the GR Research sub on Danny's AudioCircle Forum. Definitely worth looking into, for what I feel turns any good planar speaker into a way over-achieving (for the investment) full-range (ten octave!) loudspeaker. An OB/Dipole sub really is the ultimate solution to the missing bottom octave of response and limited maximum SPL output capabilities of most planar loudspeakers, non more so than the Quad 57.

bdp24 November 06, 2015 07:21

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Ct, the OB/Dipole sub is a completely different animal than any sealed or ported sub. If you want a plug & play Rythmik sub, you'll need to go with the F15HP (or the smaller E15HP; same amp and woofer, just a slightly smaller cabinet). The OB/Dipole is available only as a kit (a plate amp and two 12" woofers), the W-or H-frame the woofers are installed in needing to be custom built. But you could have the frame(s) built for you locally, from the diagrams on the GR Research site. The GR Research Forum on AudioCircle is where you can find all the discussion of the OB/Dipole sub, not on the Rythmik AVS Forum.

The back-and-forth with Rythmik you've been having has been with Brian's right hand man Enrico. You can see his set-up, including sub locations, in his profile.

Your finding of subs being "slower" than your Quads is of course very common amongst not just Quad owners, but all planar owners, especially those of electrostatics. The seeming slowness, or lack of speed, of subs comes not from their inability to follow the steep front edge of a transient, but in their inability to "stop" when the signal does, referred to as "overshoot". Rythmiks in contrast "stop on a dime" as the old expression goes. Another reason is the relatively high moving mass of a lot of subwoofer cones, the mass storing energy. Mass is often added to woofer cones to lower their resonant frequency, but not without a penalty---the added mass and stored energy decreases the driver's "inter-transient silence", resulting in a less transparent sound. Brian Ding has a patented Direct Servo Feedback design in his plate amps and woofers, and it makes for a very clean, quick, transparent sound from the custom-made 8, 12, and 15 inch drivers.

The OB/Dipole sub I thought would be of particular interest to you Ct. It is an even better match with both your Quad and Eminent Technology loudspeakers than a regular Rythmik. The sub includes the DSF design, but the Dipole design and configuration gives it several advantages over a sealed or ported sub for use with planar speakers. First, it has the same figure-of-8 radiation pattern as planar loudspeakers, with a null at each side, so the sub can be placed side-by-side with the planar (allowing the use of a higher x/o frequency, for instance the 180Hz of the ET LFT-8b). Secondly, the fall-off of output with increasing distance from a speaker is less with planars than non-planars (including subs); with a Dipole sub, the balance between it and any planar loudspeaker remains constant, no matter the listening distance. That is NOT true of a planar loudspeaker with a non-planar sub, the balance between those two varying according to listening distance.

As to locating subs nearfield to reduce possible distortion, consider this: The limiting factor in a hybrid loudspeaker/sub pairing will be the maximum output of your loudspeakers, not the sub. When your Quads have reached their maximum SPL, the subs will still be coasting! The choice of sub location can therefore be determined from other considerations, it's seamless integration with the loudspeakers being the priority, I presume. Since you can't hear the Gr Research/Rythmik OB/Dipole Sub before purchase, I highly recommend reading all about it on the GR AudioCircle Forum. It's VERY special!

bdp24 November 04, 2015 22:36

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

Did you email GR Research, or Rythmik? Rythmik lists the OB Sub kit in their product listings, but all the discussion of the sub takes place on the GR Research AudioCircle Forum. Danny is much more into them than Brian, and the GR customers are audiophiles while Rythmik's customers are more home theater guys, as are most sub owners, I take it.

The OB Sub can be used up to around 300Hz, so a stereo pair is the norm. By the way, the 180Hz x/o frequency of the ET LFT-8b (from the panels to the sealed 8" woofer) makes the GR OB Sub a perfect replacement for the good-but-not-great woofer in the ET speaker. As with all Dipoles, there is a null at both sides of each sub, where the output from the front-firing and rear-firing woofers meet and cancel. So wherever in the room you place them, they need to face the listening position. Right next to the loudspeakers is a good starting location, but the controls on the Rythmik plate amp (rotary knob for phase 0 to 180 degrees, x/o frequency, damping, volume, etc) makes blending the sub with the speaker possible wherever it is located.

Danny Richie designed an Open baffle loudspeaker he named the Super-V, and it contains the OB/Dipole sub (with a 15" OB co-ax driver for midrange and highs). An owner of a pair of the Super-V just listed it on Audiogon, so you can look at it to get an idea of the look of the sub. The owner posted only one pic, and it's not a very good one. Maybe he'll send you some if you email him.

bdp24 November 03, 2015 18:30

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

There is a DIY sub that is unusually good with Quads (actually, any dipole/planar loudspeaker). It is an offering from the design team of Danny Richie of GR Research and Brian Ding of Rythmik. Their sub is an Open Baffle/Dipole design incorporating a 12" woofer optimized specifically for OB implementation, the driver featuring the Direct Servo Feedback design of Brian Ding. Brian builds the DSF plate amp for the sub, installing in it a shelving circuit to compensate for the acoustic roll-off endemic to Open Baffle woofers.

The Open Baffle sub is an either W- or H-frame housing either two 8ohm woofers or two/three 16ohm ones. The two woofer version faces the drivers in opposing directions and wired in opposing polarity, their resulting output thus being Dipolar/figure-of-8, a distinct advantage with Dipole speakers. Gradient made a similar sub specifically for the Quad 63 in the 80's, if you recall. This new sub features much better woofers (even without their Direct Servo Feedback design) and amp.

The OB Sub DIY kit is available from both GR Research and Rythmik, and the plans for the W- and H-frames can be found on the GR website. Danny has a woodworker who makes an H-frame flat pack for he not able or willing to make his own. The sub has won "Best Bass at Show" at RMAF many years running.

bdp24 November 01, 2015 02:34

It's going to take me quite a while to read through all the responses and discussion of your systems Ct, but I'm sure gonna do it. What an interesting assortment! We obviously hear things similarly to some degree, both having old Quad and ET LFT-8 loudspeakers, and Music Reference power amps.

bdp24 October 27, 2015 08:39