In my small dedicated listening room with vault ceilings this is the best system so far. Sonus Faber Guarneri Homage's which were some of the last pair to be brought into the US along with new Jadis JA 30 Mk2 Mono Blocks utilizing KT150's and Smooth Plate Telefunken tubes, a CAT SL1 Renaissance Black Path BPX with phono. The Linn LP12 Radikal D, Karousel/Kore is the front-end with a Lyra Kleos. Esoteric DV60 SACD player, Esoteric D-05 DAC, Alternate ss amp: Jeff Rowland model 8T modded by Jeff. Room tuning devices include the Real Traps Mondo Traps, Mini Traps and Shakti Hallograph's. Grand Prix Monaco amp stands. Audio Art SE-1 power cords with Furutech connectors.Zenwave power cord PL1 with Furutech NCF 50, Zenwave D2 Ultra ic's, Graceline 1.5 meter ic and Black Cat PC-1 Silverstar power cord for Rowland. Two REL T5i subs...running high level off the amp outputs and with Signal subwoofer cables and Supra pc's. Nessie Vinylcleaner.
I know what your getting it, I too feel resonance with my T2. I believe it is a matter of the price bracket. I don't feel my B2 resonate like my T2 does. It can be hard to determine if the sub is rattling or just vibrating because it isn't heavy enough to lock itself to the floor. With the B2 at around 80lbs it is heavy enough to mitigate the effect of sitting on carpet has. The Sub Dude helped the T2 "talking" in this regard. It by no means made it close to the B2 but it helped.
About a year ago I auditioned Sonus fabers Cremona Auditor and Guarneri's with a B1 and a Mc2102. It still stands as one of the best systems I've heard. If at some point you can audition a B or G series I hope you do so. They are great pieces if one an afford it. I'm quite sure that Cremona Auditors will be my next upgrade, if only the Guarneri's were cheaper......
When you say the cabinet is very resonant, are you sure you aren't over driving the sub and hearing the driver break up? In addition to my B2 I also have a T2, during some movies when the sub was receiving a significant LFE signal, the sub would sound like it was rattling. After further analysis I determined that mass loading it from the top (with bags of beans etc) reduced the rattle but in reality I was overdriving the sub. I was just asking too much from the T2. When I substituted the B2 during these passages it just sailed right through.
I also have an Aurolex Sub Dude isolation platform for the T2. It also tightened up the T2's response and depth. I have not tried it under the B2. I'm curious to see how it differs between downward and forward firing designs. Maybe something too look into....
I agree with you, there is always something in the chain to tweak and analyze. It is fun to do but can really take away from the enjoyment. Have fun.
I would like to add that I recently added an upgraded Speak-on cable from Signal Cable to my Mc-275 Rel B2 combo. It was a very worth while investment. The sub appears to go an octave deeper and is much punchier. I have also upgraded the powercable on the sub with increased fidelity, but the upgraded Speak-on was a larger jump for roughly the same price. I recommend this to you guys.
Lapierre-Signal Cable should be able to make you a custom cable with the ground cable outside the common sheath, or perhaps each "conductor" seperate and only coming together at the Neutrik for use with your mono block setup.