Turnable Rack Vibration

I guess my point is that any top-of-shelf/under-TT treatments, if they appear to work, do so because you already have a rock solid floor, and a rock solid rack (like a Billy Bags TT stand.) But if you have a bouncy floor, it's just going to take the rack and all that other stuff with it.

To me, a solid floor is everything, and when the floor can't provide it, then you need a wall shelf (and hope and pray that the wall doesn't vibrate!)

A lot of good comments, but one is missing, so I will add it. Acoustic shield around the table. The sound engery that is in the room will directly impact the table, arm and cartridge. Play some music in the room from a different source and put your finger on the pith, arm and cartridge. You are bound to feel the vibration the acoustic engery that is flowing all over the TT. Just think what is happening when you are actually playing a record, the speakers vibrate via acoustic engery everything. In the interest of full disclosue, I am in the process of marketing 'acoshield', the solution to fixing this problem.

Thanks for all the great responses.
Buconero117: I am fortunate that the turntable is in a closet so in room vibrations, especially airborne are probably less of an issue
Nsgarch: I whole heartedly agree with you in regards to wall mounted tables. The change from going from the Target shelf to the rack is the source of all this heartache. If i was not so stubborn i would remount the wall shelf in a second. As it is i am going to try to work through the rack positioning to hear if i can improve anything. My strategy is to position the TT on the granite slab which in itself is mounted on 4 isopads placed on the top shelf of the rack.
I know from experience that increasing the mass on the top shelf of a structure / rack helps to dampen lateral forces.
I will report back once i have given it a try

Just my opinion of course, but if you have a suspended floor, it is going to be awfully difficult for you to obtain the performance you were achieving with the wall mount, so my suggestion is, unless it is impossible, go back to it.

Secondly, my experience is that with a suspended table you want light and rigid for the shelf material. With non-suspended tables massive like the granite may be ok, but granite rings like crazy so it should be damped if used at all. Personally I don't like what it does to the sound, especially without damping.

If you want to create a shelf for your rack, given the suspended table, I would look at having a shelf cut from 5/8" extruded acrylic. If it can be placed directly on the rack (replacing the existing glass or mdf shelf) you could try that. Alternatively you could try the vibrapod sandwich, with vibrapods under the acrylic shelf on the top shelf of the rack but that would be my second choice (third actually, as going back to the wall mount-with a custom acrylic shelf for it-makes the most sense.)

I went with a Target wall shelf for the same reasons but found that my sound was no longer lively. I also found that the new Target Pro shelf that I bought would actually flex under load. I wrote Target but no response.

Your answer may be a Finite wall shelf: http://www.finite-elemente.de/en/racks/pagode_signature_wall

However, this is an expensive solution compared to the Target. I've decided to take a leap of faith and build a "Flexi-Rack" made from Maple and Brass. I have a current thread going about this here: http://forum.audiogon.com/cgi-bin/fr.pl?htech&1262360875&openmine&zzKennythekey&4&5, but there's even more information over here: http://forum.audiogon.com/cgi-bin/fr.pl?htech&1158841915&openmine&zzJdoris&4&5

I'll be done with it pretty soon if you have some time. You see, I have a similar foot-fall situation. If the rack handles the foot-fall problem and also sounds real good then perhaps there's a way to get off the wall.

Anyway, I'll be continuing my thread and post my findings.

Good Luck.