This system is a culmination of many years of realizing what I value most in music. With audio, the only way to move forward is to know what you want and then work your way to achieve your goal. With that in mind, every component in this system was chosen to deliver what I value most in music. I strongly believe that the first step in any system is to choose the speaker that delivers what you want, and then choose all upstream electronics to make the speaker work.
The Acapella Violon delivers what I want. The plasma tweeter is simply without equal. It works by ionizing air from a high voltage electrode so that the air is sufficiently energized to erupt into a ball of glowing plasma. The size of the plasma flame is modulated to produce sound. No moving mass, no inertia, no coloration from cone material. This tweeter sounds like nothing. There is no metallic ring like you would get from a metal dome tweeter, and no softness associated with textile tweeters. Sound simply emerges fully formed, the speed and dynamics is unmatched. It just sounds real. This is without doubt the best tweeter technology in the world.
The midrange horn very nearly keeps up with the tweeter. It covers a large range from 500Hz-5kHz with shallow (-6dB/oct) slopes either end. The dynamics from the horn match the tweeter, and it excels in delivering instrumental timbre and loads of inner detail.
The weakness in the system is obviously the woofer. The overall quoted sensitivity is 91dB/W/m, and I am certain that the horn and tweeter were padded back to match the woofer. The drivers are 10", and arranged in a pseudo-isobaric configuration. Strangely, the external woofer is run from the crossover (500Hz, -6dB/oct), but the internal woofer is run directly from the speaker binding posts - i.e. full range. The bass is muddy, sluggish, and there isn't much of it. It obviously sounds disconnected from the horn and tweeter.
Furthermore, the speaker exhibits a wicked impedance curve with 600 Ohms for the tweeter, 8 Ohms for the midrange, and down to 2 Ohms for the woofers. This further exacerbates bass problems when run with valve amps.
I was obviously aware of these problems when I bought the speaker, so why did I choose such an obviously compromised speaker? The answer is - I strongly believe that midrange and treble should be gotten right first. If your midrange and treble are not right, you will spend endless sleepless nights trying to fix a problem which may not be fixable. Bass, in contrast, is relatively easy to fix.
I am about to embark on an adventure to fix the bass on my speaker. The first step is to purchase a solid state amplifier to bi-amp. The next step is to purchase a DEQX to control the phase response and group delay of the individual drivers. After this, I will remove the crossover in the bass unit (converting the speaker to active), and change the woofer to a more suitable driver. Finally, I will build a custom crossover to go before the midrange/tweeter, which will prevent the ADC/DAC stage of the DEQX from contaminating the all-important midrange and treble.
Last but not least, I will return to an analogue source, but such a purchase is still very much on the horizon.
Watch this space.
Previous entry ---
Thanks to AudioGon, I became aware of this speaker. After salivating at some of the nicer Acapella setups here I had to go have a listen. Boy, was I captivated. The most revealing speaker I have ever heard. The plasma tweeter is something else!
I am currently also upgrading from the Cary CAD-805AE to the Cary CAD-211AE, which should allow me to control the Violons a little bit better.
I named this system "Southern Lights" after Eliotswede's Acapella Violon system ("Northern Lights"). After all, i'm in Australia!
-- Old description below --
Years ago I became aware of the sweet combination of Cary amplification and ProAc speakers. It has been my intention for a long time to replicate this system and I finally got the opportunity to build my dream system from scratch.
3 way speaker with plasma tweeter, horn midrange, and conventional woofer. The most astonishingly natural sound I have ever heard. Sounds seem to emanate from thin air, free of distortion and coloration. This picture was taken next to my old ProAc D38's.
Cary Audio Design SLP-05
This is an outstanding preamp with faultless sound. It takes forever for the tubes to run in. The first time I powered it up it was shockingly harsh and unmusical, but this settled down after 24 hours and is now gone.
Cary Audio Design CAD-211AE
110W of push-pull triodes. Incredibly grunty.
Marantz RC-9500 universal remote
The HT and 2 channel systems are tied together with this programmable remote. One press of the button starts a macro which ensures that all the correct settings are chosen.
Acrolink Mexcel 7N-S9000
Simply unbelievable transparency
Acrolink Mexcel 7N-A2070 XLR
Astoundingly transparent. With my last cable I was wondering where the midrange had gone. Well, now it's all back :)
Microseiki BL-99v
Micro-Seiki BL99V turntable with vacuum hold-down.
Lyra Lyra Dorian
Lyra Dorian cartridge
SGR EL30S
SGR EL30S solid state stereo amplifier, 300W. For bass duties only.
JL Audio F110
Pair of JL Audio F110 subwoofers.
DEQX HDP-3 preamp/processor
The DEQX HDP-3 is used to measure the system and will be removed from the loop as soon as development is done.
I had a chance to demo the Acepella Violin at the show and also at my audiophile friend house. I have to say the plasma tweeter by far was exemptional, the midrange was very sweet but at the same time very seductive. I felt in love with the overall tonal balance of the top end and to the mid. Like you had mentioned, the bass was the weakest point in the speakers. I totally agree with you on this point. I feel that it has to do with the enclosure and the size of the drivers. No way you can get enough bass on the cabinet with 10 inches isobaric.
Very nice system with the really musical speakers! I am using Acapella Violin MK IV and would like to hear from you your equipments facilitiating these speakers.
Thank you! I suppose the all-out solution for me would be to use a high end external crossover like the Pass XVR-1 crossover not to contaminate the mids/highs, feed the output of the lows to a DEQX HDP-4 to perform speaker and room correction for the low frequencies, feed another pair of Krell FPB 750mcx monos driving the portion of the passive crossover that feed the 15" and 8" woofers (I believe cross at about 300hz, but have to check). Aprox. US$25K.
Have you tried the new Deqx HDP-4? They are supposed to be way more transparent than the HDP-3.
Hi VN, sorry for the late response. I don't often come to Agon these days.
You are correct, if you get an active external crossover, each channel will have to have its own power amp.
You COULD do what you suggest (pair of Velo DD18's) but really 100Hz is much too high for them. They will go up that high, but they are much happier doing 10-50Hz. At 100Hz they start to become directional.
Thank you for the feeback about the expected decrease in transparency.
The problem the active external crossover is that I would have to buy a new pair of mono amplifiers (or one stereo) for the 15" woofers, and bi-amp the speakers correct?
For the cost of buying a new pair of Krell FPB-750mcx, it would be cheaper and better to buy two Velodyne 18DDPlus, cross them at 100hz, and use their room mode correction. Don't you think?
Hi VN, I would highly doubt if it would be transparent enough above 100Hz to not lose any detail. I would suggest you do what I did - bypass the internal crossover, get an active external crossover (like Marchand), and run the lower frequencies through an inexpensive DSP like Behringer or MiniDSP. Those should have enough resolution to not do any harm to lower frequencies. Higher freqs is a different matter!!
I stopped using the tact 2.2x digital to digital for room mode correction because they were not transparent enough. Now I am thinking about trying the deqx hdp4 digital to digital in-line configuration to feed my playback designs mps-5 and krell phantom. Do you think it may be neutral enough above 100hz not to lose detail? I want it mostly for room modes below 100hz, but want no deterioration Above it. Thanks!
If anyone is interested in pictures of the surgery, here they are.
http://www.pbase.com/amfibius/image/92182147 Standard exterior of the bass cabinet of the High Violon
http://www.pbase.com/amfibius/image/135344562 Front panel removed. To get the front panel off, remove all the Allen bolts on the front except for the bolts holding the driver in. The panel will remain firmly stuck into the cabinet - this is because the driver is glued to the bracing from within. To remove the driver, remove the crossover to gain access to the back of the driver. A sharp tap with a hammer will break the bond and the panel will pop out. Be ready to catch it! The black cloth covers the second internal driver in the High Violon. Note the horizontal bracing behind the front driver - this is what the back of the driver is glued to.
http://www.pbase.com/amfibius/image/135344509 Internal bass driver removed. Note the bolt behind the rear driver to provide support.
http://www.pbase.com/amfibius/image/92181955 Picture of the hidden part of the front panel with the standard driver in place.
http://www.pbase.com/amfibius/image/135344563 http://www.pbase.com/amfibius/image/135344518 http://www.pbase.com/amfibius/image/135344515 http://www.pbase.com/amfibius/image/135344521 http://www.pbase.com/amfibius/image/135344513 Comparison of the standard and new driver. The standard driver is a SEAS CA 25 ACA, which should cost about $70-80 to buy. Note the stamped basket, small motor, and flimsy spider compared to the new driver.
http://www.pbase.com/amfibius/image/135344565 Because the motor is deeper, some surgery is required. The bracing needs to be cut 40mm to provide clearance for the motor. Don't worry, there is still adequate bracing left to provide stiffness for the cabinet.
http://www.pbase.com/amfibius/image/135344566 The mounting holes do not exactly line up, so the driver was rotated 5 degrees and new mounting holes drilled. Note the temporary duct tape to protect the port at the back of the driver from dust. Remember to remove this before mounting the panel back on the speaker!
I don't think that the midrange driver relies solely on the natural band pass offered by the horn so the resistor must be within the crossover network located inside the enclosure that the horn is attached to. I have no idea how to get to it. I wish I could help but I never opened up my Violons.
Hi Kotjac, I am thinking of removing the padding resistor for the midrange horn! I am not sure how to get at it. I would suspect that it lives in the flange where it slots into the bass cabinet. Would you happen to know?
And yes it did cross my mind that I would be able to get away from the Cary 211 and go back to a SET. A friend of mine has the Yamamoto A-08S which I might be able to borrow if I can improve the efficiency of the midrange horn. The only thing stopping me would be the massive depreciation I would have to swallow when selling my CAD-211's - I bought them new :(
How about going a step further and removing the padding resistor on the midrange horn? The midrange horn in the Violon is heavily padded to bring the efficiency down to the level of the original woofers (91dB), however it is capable of at least 94dB efficiency (the same midrange driver/horn is used in the 94dB efficient Triolon). By removing the resistor you would end up with a high efficiency system that can be easily driven by a 300B or 45 SET. A properly executed low powered SET amp should sound much better than your Cary amps. Crossed over at 600Hz it will be driving a limited bandwidth so even a 45 should be fine.
A few months ago I heard the CAD 211AE's on some custom built 95dB efficient horns. The sound was very good. The owner then switched to a 2 wpc Yamamoto A-08 45 based amp and there was simply no going back to the 211's: the Yamamoto was so much more tonally refined, transparent and alive, simply magical. The Yamamoto is significantly cheaper than your Carys. Just some food for thought.
I have finally completed surgery on the bass cabinet and installed a new driver, replacing the standard drivers that came with the Acapella. The work was done by SGR Audio, a speaker design company in Melbourne.
I have always thought that the bass does not suit the character of the midrange horn and tweeter. The bass is noticably heavy, muddy, and flabby - which is in total contrast to the superb articulation of the horn and tweeter. Inspection of the bass cabinet reveals that the cabinet is very solidly made, but the woofer configuration is somewhat unusual. There is an external woofer connected to the crossover, and an internal woofer which runs straight from the binding posts - i.e. running full range.
The first step I took was to buy a pair of subwoofers and use an active crossover to remove all bass frequencies below 80Hz from the bass cabinet. The idea was to minimize woofer excursion and clean up the midbass. This helped tremendously but the problem was still there.
The next step was to purchase a solid state amp and bi-amp the speaker. The improvement was minimal.
After this, the next step was to bypass the internal crossover, disconnect the internal woofer, and connect the SS amp directly to the external driver. This yielded a tremendous improvement, but the problem with the flabby bass was still there.
The only logical next step would be to replace the external woofer with a new speaker driver. SGR Audio had a design for a high efficiency 10" woofer (98dB and 8 Ohm). Installing it required some surgery to the bass cabinet - the support brace at the back had to be cut to provide clearance for the deeper motor of the new driver. New mounting holes had to be drilled in the front baffle, and the hole had to be routed to make way for the thicker basket of the new driver.
The final result has the new driver connected directly to the SS amp with an active crossover upstream. The result is astounding - the midbass is SO MUCH cleaner. There is a certain lightness about the way it goes about its business. It very closely matches the midrange horn and tweeter in speed and tone.
For once, this speaker sings as one without any obvious disconnect between the drivers.
All my major modifications are over. From here on the overall system architecture will remain the same, but my future plans involve refinements to the crossover and amplification. In short - I can be a normal audiophile again and put the speaker engineering hat away.
That's a good idea kotjac, except that the speaker will not sum up to be flat at the crossover point if I did that. Still, it is only a matter of pulling out a plug. I might try that later :)
Have you considered not using the Marchand as a low pass for the horns and instead using it only on the woofers to match the high pass on the horns (probably a 12dB slope)? In your current configuration you have two crossovers (the Marchand and the passive inside the horn box) in the signal path to the midrange horn and the tweeter. The Marchand is pretty good but I'm worried it may not be completely transparent. Just some food for thought...
Hi Kotjac, I used a 48dB/oct slope for all crossover points. The Marchand allows me to do that.
You are correct that the speakers have two woofers in the cabinet, but the second woofer was in a bizarre configuration. As I have mentioned elsewhere, in the default configuration it is connected directly to the speaker binding posts, thus bypassing the crossover and relying on the natural roll-off of the driver. Further, it is mounted at 45 deg, and there is acoustic material muffling the output of the driver. A speaker engineer friend made this discovery, and he could not figure out why the Acapella designers did this.
I have therefore disconnected the interior driver. It is a very easy modification to make - just undo the Allen bolts on top and the crossover pops right off. Find the the cables from both the drivers, and snip them both off. Find the cable that runs to the exterior woofer, and connect that directly to the binding post. Should take you 15 mins per cabinet if you have the right tools!
I can't post measurements on the 'Gon, so perhaps I might do a write-up on another webpage.
Hi Keith, What slope did you end up on the 600Hz high pass: 6dB, 12dB 18dB or 24dB? You mention that the SS amp is hooked up directly do the driver. Your speakers have two woofers per cabinet. Is the internal woofer still hooked up? Did you experiment with using both woofers vs. a single one? I would think that there would be no benefits of using the internal woofer now that everything below 80Hz is routed to the JL Audio subs.
I would be very interested to see your measurements.
Mickep, the JL Audio can be integrated until it is more or less blended - so the crossover point is not measurable, nor is it audible.
FWIW I have just completed a pretty substantial upgrade. I have always had problems with the bass not integrating properly with the midrange horn and tweeter. This is what I have done in steps:
- Use a line level crossover to remove everything below 80Hz and send it to the subwoofer. Everything above 80Hz goes to the Cary amp and the rest of the speaker.
- Purchased a SGR EL30S solid state amp and then bi-amped with the Cary's on top.
- Purchased a Marchand 3-way crossover - 600Hz to Cary (then to horn/tweeter).
- Removed the crossover from the bass cabinet, so the SS amp is hooked up directly to the driver (i.e. active configuration) --> this is my current configuration.
The modifications have made a world of improvement to the coherence of the sound. If you are interested, I could do a more detailed write-up with my measurements and how I tackled the problems.
System edited: System edited - a lot of new hardware added: - Analogue system: Micro-Seiki BL99V turntable, MA505 Mk2 tonearm, Lyra Dorian cartridge, RCM phono stage. - Speakers now bi-amped with Cary CAD-211AE on top, and SGR EL30S solid state amplifier on bottom. - DEQX purchased to help with bi-amping. - A pair of JL Audio F110 subwoofers has been added to the system
Kevin, I have to hang my head in shame. I am using a Behringer CX2310 crossover to remove signal from the main speakers. This means - I have a $100 crossover inserted in the signal path in a system where the cheapest interconnect is $1k. I was hoping that nobody would ask!
I arrived at the 70Hz crossover point by ear. I have software and calibrated equipment to measure the frequency response, but no matter where I set the crossover point I can get nearly flat frequency response. The advantage of the Behringer is that all the settings can be set by tweaking the pot, rather than something like the Marchand where you change the settings by inserting daughter cards.
If I go higher than 70Hz, the bass starts to become directional. If I go lower, the benefits of the subwoofers are not realized as much. It is probably 70Hz +/- 10Hz, my ears aren't that good!
The plan is to replace the Behringer with a Marchand. Or maybe a Bryston. I'm still investigating.
Hi Amfibius - What crossover / high-pass filter are you using between the pre- and poweramp (e.g. Marchand, Pass Labs etc)? How did you arrive at 70Hz and not some other frequency for the crossover point? Finally, where did you position the subs in your room.
I'm glad to read about the benefits you've listed as I plan to do the exact thing set-up wise. I'm planning to insert a passive high-pass filter before the main speaker's amp and put a parametric EQ ahead of the subs to tame room bass nodes and use the sub's crossover capabilities. Pretty much the same as you have expect the additional parametric EQ . . .
Hi Kevin, thanks for the response. I haven't updated my system in a while, but I have now inserted a pair of JL Audio F110 subwoofers. A crossover sits between the preamp and power amp, and removes all bass below 70Hz from reaching the main speakers. The benefits are many:
- more versatile placement of the subwoofers - increased apparent amplifier power - less cone breakup from the main speakers as the excursions are now lower
It has worked wonders.
I do have acoustic foam. And I am trying to find Floyd Toole's book.
Amfibius, To improve your system bass have you considered the following actions: * bi amp the bass with one of Cary's solid state amps to keep the same 'house sound' to match with the upper frequencies of your Cary 211 amp * insert an analog parametric eq between preamp and say a Cary solid state amp to reduce room bass peaks * consider adding a pair of subwoofers to add to better room loading * bass traps will also help
Finally, what acoustical room treatments have you? Also read Dr Floyd Toole's latest book which has a seperate chapter on better bass for small rooms.h
All the additional analog to digital and digital back to analog conversion that the DEQX performs simply cannot be without an impact on the sound. The loss of resolution and dynamics that you're describing is thus something to be expected when the DEQX is fed with an analog signal.
I think that the ideal way to experience the full potential of systems such as DEQX or TacT is to feed them with a digital signal, let them handle all the necessary crossover, time alignment, phase adjustment and room correction functions and then use their digital outputs to feed quality external DACs followed by a nice multichannel preamp (in your case four channels would be required) for analog volume control. Of course this way you would not be able to use SACD or analog sources. Based on my recent experiences however, the future belongs to music servers. With the increasing availability of high resolution downloads I just can't imagine SACDs surviving for too much longer. If, however, you're thinking about getting an analog rig, then I don't think you would ever be satisfied with the DEQX system. There are other options though. In my system I am currently using an analog parametric EQ device made by Rives Audio (PARC). I am bi-amping my Violons (Audio Aero Prestige SETs on the midrange and treble and Belles 350A Reference on the bass), and the PARC is inserted between the preamp and the bass amp, thus having no impact on anything above 500Hz. Rives claims that the PARC introduces no intrinsic time delay but I haven't been able to verify it. All I can say is that in my rather difficult acoustically room, the PARC brought huge improvements in bass definition and articulation. The bass still doesn't quite match the amazing speed of the midrange horn and the plasma tweeter but it is pretty good.
With the right electronics the Acapellas' midrange and treble are the best I ever heard and although bass is not as outstanding as the rest of the spectrum, I could happily live with it. I think that part of your problem lies in the electronics and you're hearing too much of the Cary signature sound in the bass. I used to own the Cary SACD 306 and although it is a very good player, I found it's bass slow and muddy compared to players such as Wadia 581 or EMM CDSA. The Cary pre doesn't have a world class bass either and I think that everybody would agree that the Cary 211 amps cannot quite deliver what the dual 10" woofers need.
