Isolation for a table for floors with movement

Jsawhitlock is correct but you may want to use 2 jacks with a 4x6 spanning across the jacks and supporting all the joists which are under your system. Depending on the span you might use a 3rd jack in the middle. For a footer use a 4x8x16" solid cap block. Of course this is with the assumption that your system is on a 1st floor with access to the crawlspace or basement below.

Of course, you could isolate the table from the floor by suspending the table from the ceiling, using 4 guy-wires (or picture wires) attached to a solid self with the table on the self. I have and footfalls, etc. have no effect.

Salut, Bob P.

Inpep.., a great idea and one I used extensively in the 70's and 80's. I've mentioned this on other forums and it seemed so foreign to some that I don't even mention it anymore.
I would not hesitate to do so today as long as you can get solid support from the ceiling joists.
My 15-20 lb TT of the 70's wasn't a problem to hang. A modern mass loaded 50 lb TT might make me extremely careful and somewhat worrisome. So i can understand anyone's skepticism of the hanging method

Artemus, that is not the real reason why some 'pooh-pooh' that solution. Nobody makes any money from that solution and one can't sell guy-wire for exorbitant audiophile prices, but then maybe one could.....? And of course, there would be the debate about the material of the supporting shelf.
Frankly, if I could do it properly, I would insert islet screw directly into the turntable and suspend from there and eliminate the shelf completely.
My turntable is an Oracle Alexandria MK III with piano finish, so I don't want to ruin theat beautiful finish.

Salut, Bob p.

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.