Isolation for a table for floors with movement

From a builders perspective, you are on a road towards disaster with that plan. Concrete is extremely heavy and needs to be engineered and built with steel rebar to be self supporting with a load. This is not the kind of thing you do with wooden joists incorporated
in all probability, your floor is fine since it is already over engineered from what i can tell. Two layers of 3/4 plywood is not normal procedure. If you have I-Joists, they are very rigid also.

Hi Artemus_5 Thx,

yes they are I-Joists and I would have used re-bar etc. in actual fact I would have had a engineer tell me exactly what to do. Forward, I spoke to my friend who is an engineer and there is a way of doing it but other issues could arise down the road so I have decided against doing it.

If you must beef up your floor you could remove the sheetrock below and put new joists between the existing, spanning from bearing wall to bearing wall. This would make for 8" o.c. which should make for great rigidity.
Also, consider that I have a 130-140 lb turntable (Teres) which sits atop a custom mass loaded stand which weighs another 100 lbs or so. This is sitting on a floating wooden floor using 10" joists @ 16" o.c. with a single sheet of 3/4" plywood flooring. I can jump in front of my TT while it is playing with no detrimental action to the TT's performance. However, I do have it braced from beneath. But it is not extreme bracing. Only a few uprights were needed.
Just something to consider

It's been a while and wanted to update this thread. Unfortuantely due to the design (open concept basement) I could not do any upright support post so I did some further research and .....

I purchased a custom made Minus K platform, works great!

I know longer have the TW Raven One table, I went up the TW food chain to a AC3 and now I'm a proud owner of the Black Knight.

Aurios bearing work quite well and don't cost a fortune.