Isolation Advice Needed

I also have wood floor over crawl space. It is springy, has been problematic, luckily solved now. It was built in 1951, I think with ’green’ wood (not properly dried) as so much building occurred after WWII. More problematic than most suspended wood floors.

My Thoren’s TD124 Magnificent, but it’s Bearing was very susceptible to vertical motion, traded it for that reason, still miss it.

My Audio Technica AT120, much lighter player, was ok but cautious steps when close. No dancing or kids running nearby please.

Current JVC Victor Heavy TT81 player in a heavy CL-P2 plinth was similarly ’cautious approach’ until I put it on 2" x 2" isolators, they can be seen in 7th photo here.

I have since wrapped the blue with black tape, far less noticable

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A major part of my problem/solution is: the floor slopes immediately from the wall, the front of the rack is 3/4" down. Then the floor levels out.

Previously I had little blocks under the rack’s ends which were recessed from the front a good bit. Then I would level the Turntable on the top shelf. I realized, all the weight, rack, 80 lb amps, two double wide shelves of equipment was tilted forward, much of it in front of the recessed end panels, thus any vibration involved ALL that weight forward of a fulcrum point.

I built new side supports, tapered as needed for 3/4" extra in the front, and extending a few inches in front of the rack, (also seen in the same 7th photo) so the entire rack and equipment is level on that sloping floor, all the weight now behind the front fulcrum point.

Each glass shelf has it’s own firm rubber isolators, and top equipment is on racks I designed with firm rubber feet.

@livin_262002, here's another two cents from the peanut gallery:  wait 'til you get set up in the new house and see if you need any isolation.  With all the additional weight put on the floor(s) from furniture, etc., you may not need to spend any cash on isolation. New "stick-built" construction, nowadays, uses 8' X 10' wood floor joists 16" OC, sometimes cross-membered; sometimes not. Sometimes, builders will go 12" OC with the floor joists to add more strength; sometimes, they'll even go less than 12" OC or "marry" (double-up) floor joists and cross-member them to add additional strength (e.g.  accommodating additional weight of tile flooring). My house has single 8' X 10' floor joists 16" OC for the first floor, wood flooring and wall-to-wall carpet over that in my sound room (i.e.  14' X 23' living room). I've got a Salamander Synergy rack on its regular adjustable pad feet (i.e.  no spikes) and I don't need any isolation for my system.  My TT weighs a little over 24 lbs.  Rega is a proponent of low mass design. Hence, the P6 weighs less than half of that. It was on my short list when I was shopping for a new TT. However, I eventually decided I liked the idea of more mass (i.e   heavier) for a TT. My amp is just under 40 lbs. and the rest of the equipment & stuff I have on the Salamander probably adds another 30 or 40 lbs. or so. I do have a lot of bookshelves in the living room, though, one of which is floor-to-ceiling. So, I'm sure the weight of all the books adds a lot. I've had plenty of parties & people over while entertaining and have never had any issues with vibration, footfalls or any of that sort of thing. I've also occasionally had small children over. However, the sound system, especially the TT, is not in use when small children are around, for obvious reasons, or I'll sit with the kids to make sure they behave if they want to listen to some music. Frankly, I don't trust anyone anywhere near my TT, except my closest audiophile friends. As long as people aren't dancing up a storm in the living room, jumping up & down and doing stuff like that, my sound room is just fine.

@whart Active air suspension, as you aptly pointed out, might leave table in an uneven profile for a short time while it tries to adjust. MinusK seems to be a better all-round solution, if needed.

@steakster Thank you, did research those too. All footer suggestions are great for electronics just have to choose the right one for mine. OTOH, for TT I'm looking for a future proof solution.

@jerrybj Lol

@henry53 Thank you, I have been researching those as well. I did get a video of the crawl space and as @noromance hinted, there are concrete piers with smart jacks at regular spans (8 ft apart) under girders. So the floor is not bouncy but given the empty space (crawl space), I can see vibrations can amplify and travel along the floor.

@elliottbnewcombjr  Thank you for a detailed explanation of your solution. The floor has no bounce at all (at least for now), My main concern is what I explained above. Love your JVC TT though.

@oldaudiophile Thank you for the insight and suggestions, I'm yet to decide on the furniture for the room. Not sure what the mrs will want to put in there :). My older kid loves to dance when I have the music playing so that's the other reason why I've been researching. I might go for a heavier TT later this year so what ever isolation solution I decide on has to be future proof.

I agree, I should wait until I make my decision but wanted to get some great suggestions in advance so I have enough data when its time. 

Best Regards

The equipment I listed in my original post are only the ones that I thought were VERY sensitive to vibrations. I have the following additional components ...

1) Tandberg TD20A SE (Reel-to-Reel)

2) Tandberg TCD-3014A x 2 (Cassette decks)

3) Oppo BDP-105

4) Sony 75ES DAT

5) Genesis Digital Lens

6) Benchmark DAC

7) ExactPower EP15A

@livin_262002 

I am an enthusiast of Symposium Acoustics products.  The owner, Peter, is easily available to speak with by calling them direct.  He will guide you very well, regarding your particular situation and needs.  Symposium offers a turntable specific platform called the Segue ISO.  This platform is made of the constrained layer design, like all Symposium platforms, and also uses springs which are available in several sizes as needed per the weight of the turntable.  The Segue ISO comes in several standard sizes as well as can be ordered by any custom size that you may need.  Try contacting Peter and see if he has to offer what will satisfy your needs.   The website is very helpful and detailed.  Certainly worthy of your effort.  Best to you.