Thanks for the tips, I do have 4 isoacoustic orea under each sub. I have 6 soffit bass traps from gik acoutiscs, two with the membrane for even lower frequency absorbers, 6 monster bass trap panels (on the wall above and right behind me) along with 6 of those art diffusion/absorbing square panels. I'm sure adding isolation to the rack would help, but to be honest, I do not consider int my priority at this point. The glass is obviously a problem, I have a thick curtain I close when listening and that helps quite a bit, but not ideal. This is a living room after all and will need to remain so.Maybe I'm backwards. The biggest single change in my system was the ROOM. It had very little to do with equipment either.
That room and the way the equipment and subs are NOT decoupled would make make a huge difference. I don't see any changes in gear needed at ALL. Just the room being tuned. Save your money.. Helmholtz adjustable traps. Two more subs and move the subs away from the gear.
ADD Air bags, pods or springs for the racks, main speakers and of course the subs..
Cost 2-3k, improvement 50+ % in what I see alone. Gear swaps would be sideways at best.. Same with speakers. Tune with the traps, add a floor to ceiling drape on the huge reflective glass (left) and decouple. No spikes or any of that mess they don't work in every direction.. That is a problem, it adds a timing issue for the lower octave from the sub speakers and room vs the floor. The floors response is quicker than the room response. (smear). If you have bottom firing subs, do yourself a favor and look for anything but that, unless they are slot loaded with a butt plate and can be decoupled..
I am thinking about testing something else right behind the listening position, maybe the thick bass traps are too much? On the other hand, diffusion so close to the listening position is generally regarded as a mistake and needs to have a minimum distance of clearance.