Isolation for a table for floors with movement

hi Dev,

there are lots of good ideas in the above posts. my current room has 6" of concrete on a ground floor. my previous room was a suspended wood floor over a crawl space. i did pour some concrete pads in the crawl space and rig some cross members and brace under my gear rack and my speakers and that did make a big difference. it was quite easy to use shims to take almost 100% of the 'flex' out of the floor.

i use a Grand Prix Audio rack system, and have used a Halcyonics.

i read thru this thread a couple of times but did not see you specify exactly what is under your floor. is it a basement? crawl space? how is the floor and the ceiling below constructed? can you get to the supports for the floor joists?

the more specific info you can give, the more likely someone might have already solved your problem and can share the solution with you. it is dramatically cheaper and more effective to firm up your floor than to try and isolate your gear from a flexible floor.

Dev,

thanks for the details on your set-up.

from what you say it sounds like the floor is the way it's going to be. the only other 'floor' idea is to get something large, dense and heavy and try it under your rack. it's possible it might 'ground' the floor sufficiently to reduce flex. but it also might make things worse.

so what you can do is to address sources of resonance in the room which will transmit feedback, which is primarily your speakers. there are a number of de-coupling footers or platforms which can somewhat isolate the speaker feedback from the floor. right now you likely use spikes into the subfloor thru your carpet for the speakers.....which effectively transmit the speaker feedback.....you need to go the opposite direction and decouple somehow. then listen. it might be that spikes into the floor are best, but not likely while playing Lps.

then i think you are on the right track with the various multi layers of isolation you have mentioned. you might speak to TW Acoustic and see what they recommend for that tt in your situation.

good luck.