Turnable Rack Vibration

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.

Kenny: When you say the Target Pro shelf "flexed under the load" are you saying that the rack itself flexed or the shelf material (MDF shelf).

If it's the rack itself that's flexing, I'd say dump it. If it's just the shelf material you could experiment with a number of different types of shelf materials (some more expensive than others-but some very cheap) that will give you different sound qualities and definitely will not flex.

The MDF is pretty crappy and a definite weak point with the Target rack, both from a structural and sound quality standpoint.