Turnable Rack Vibration

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.)

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.

Kenny: That's too bad. That would move me very quickly away from the wall mount as well! I have an older Target wall mount, the one which Nsgarch described with triangular bracing. It is solid as a rock. Too bad that Target has cheapened the product.

"Dan, for what it's worth (and I've been using Target wall shelves since 1990 ;--) one of the best (and easiest) mods one can make to the MDF shelf that comes with the unit is to make a "constrained layer" damped shelf out of it. Start with a second sheet of denser material the same size as the MDF shelf. I use 1/4" glass, but you can use Corian, acrylic, granite, aluminum -- whatever, as long as it's a harder than the MDF. Then get a sheet of 1/8" - 3/16" thick (maximum) dense foam or sheet sorbothane. Spray the bottom surface of the MDF and one surface of the second material with 3M 88 Spray Adhesive and press the sandwich together, place it on a flat surface and set a couple of cinder blocks, side-by-side on top for 8 hours (you want the adhesive to dry out under pressure!) You now have one of the best constrained layer damping systems in the world! If you can use spikes under your TT, that will increase performance even further."

Nsgarch: Thanks very much for posting this. As I mentioned earlier, I have an older style Target wall mount that I acquired recently. The MDF shelf was warped and I've never been fond of MDF on its own anyway so ended up buying an appropriate sized piece of 3/4" baltic birch at first before experimenting with extruded acrylic as a shelf (using a Michell Gyrodec).

The acrylic had much better sound quality than the baltic birch but the plastics fabricator sold me a 3/8" inch thick piece when I probably should have gone for 5/8". In any event, the 3/8" flexed a bit under the weight of the Gryo which I was not super comfortable with.

I've always really wanted a Neuance shelf, but alas, Ken Lyon is no longer producing them, so after reading your post above I went out to an upholstery shop to seek out some high density foam. Ended up with 1/8" high density neoprene foam (it can actually be rolled up very tightly and will stay that way, almost like a piece of fabric) and then bought a piece of 3/8" baltic birch. I bought adhesive but actually never used it. The configuration is table, 3/8" acrylic, neoprene foam, 3/8" baltic birch onto the spikes of the target wall mount (metal blanks under the baltic birch at spike points).

My "sag" with the acrylic on its own has been eliminated; I was a bit surprised at the improvement in sound quality. The "constrained layer" shelf is definitely doing its job. Improved high and low frequency performance and a much more transparent and natural sounding midrange. The key words are natural sounding. The baltic birch on its own, as well as higher mass phenolic shevling were a bad match with my Gryo, "enhancing" detail but at the same time considerably hardening up the sound. Glass, marble and granite on their own all have similar, even nastier qualities.

In short, $10 for the neoprene high density foam and another $10 for the baltic birch combined with the acrylic I already had have worked together to make a very good shelf.

Thanks for the info.