TT on Symposium Super Segue - slate or maple underneath?


I've gotten a Super Segue for my VPI Avenger. I have various things on hand I can place under the Symposium. I wasn't sure if a 3" thick maple block would work better than a 1/2" thick piece of slate. The whole thing will be sitting on top of my wooden equipment rack. I know ideally I should try both to see what sounds better, but hauling a 70+ pound TT on and off shelves for listening tests (not to mention moving a 3" thick maple block around) can be a bit of a pain. I'm hoping someone here has had some experience with what they've felt works best under a Segue, so I could try that first.
tonyptony
@bdp24 the Symposium Foundation, unlike the Symposium Osiris does not incorporate rollerblocks. I should know as I have an Osiris Ultimate for my main component rack (ARC Ref 6 preamp and Manley Steelhead) and two Foundations on either side for my two vintage tables, a modded/hotrodded TD124 and modded Garrard 301. The advice I received from some of the best minds in vintage tables is that direct vertical energy dissipation via the Foundation is superior to multiplanar energy dissipation. 

Right @fsonicsmith, the Symposium Segue (and Super Segue) don’t include a set of the Rollerblocks; the consumer must buy them separately and put them in place between table and Segue, or under a no-spring (presumably) Symposium platform.

My situation and needs are different, as my VPI Aries 1 has a separate motor pod, my HW-19 has a separate SAMA, and my Townshend Rock has it’s motor bolted onto that table’s Plaster-Of-Paris-filled "upside-down baking pan" plinth, which is very vibration resistant and non-resonant. My interest is in a support platform that is as stiff and non-resonant as possible, something I would think every turntable will benefit from.

At the hardwood shop I visited today, I checked out all the various thicknesses and number-of-plies plywood they stock. Remember the base Art Dudley made for his TD-124, which he wrote about and pictured in his Stereophile column a few years back? He chose Baltic Birch ply as his material, and the stuff is incredible! An 18mm thick sheet (just shy of 3/4") is 13-ply (the 1" version is 18-ply), each alternating ply grain-orientated 180 degrees to it’s two neighbors, with layers of glue joining all plies. The plies are void-free, and the resulting structure is extremely stiff and fairly non-resonant, the resonant frequency being relatively high, which is of course desirable, especially for a turntable (as well as CD players and tube electronics). With constrained-layer damping employed, it will be VERY non-resonant. I’ve done it with ASC WallDamp, which works great in this application (not to mention it’s intended use---between two layers of sheet rock in wall construction. Audiogon member folkfreak’s room was as so constructed, and his room is amazingly "quiet" (the walls are silent. You don’t realize how noisy walls are until you hear a room built using WallDamp.).

Baltic (Russian) Birch is available in both 5’ x 5’ and 4’ x 8’ sheets, and the 18mm thickness is priced at under $100 for either. A 4’ x 8’ sheet can be cut into twelve 24" by 16" pieces; twelve Baltic Birch shelves for less than the price of one 3" thick 22" x 16" maple block! Put two together with constrained-layer damping between them, and you have six shelves far superior in stiffness and non-resonance to a 3" thick maple block. I myself don’t want my shelves to have the sound or tonality of maple, I want them to have no sound at all. And that’s achievable!

By the way, the shop also had what is called maple (or walnut, and many other woods) ply, but all that is maple about that plywood are the two outer/surface layers, for looks. I actually like the look of birch; it’s modern in a Scandinavian/German kinda way.

Where's a good place to buy ASC WallDamp?

It's funny to see the resurgence of Baltic Birch. Dick Shahinian, bless his memory, knew how good such material can be for building speakers. Although IIRC he used Finland Birch, back in the days when I think the stuff actually came from Finland. I agree it's great stuff.

Tony, you can get WallDamp directly from ASC in Eugene Oregon, I believe. They (Acoustic Sciences Corp.) offers in in 4" squares, but also scrap pieces by the pound, trimmed pieces from end of rolls or installation jobs they do. I ordered some pieces years ago cut in the exact size (22" x 16") of the top (MDF) shelves of my Solid Steel racks, then bought extra top shelves to make doubled/constrained-layer damped shelves for the racks. I’m going to do it again, this time with Baltic Birch.

Speaking of Baltic Birch, I misspoke above when I said the plywood has each layer 180 degrees apposed in grain direction to it's two neighbors. That makes no sense! They are actually 90 degrees opposed, which of course greatly strengthens and stiffens the plywood, just what you want in a shelf or platform.

Hi @bdp24 - couple questions for you re: your use of WallDamp

- how much did you use - 1 layer? more?
- thinking of using baltic birch and something dissimilar, maybe slate as you suggested above - again 1 layer of WallDamp?

I guess this could lead to endless experimentation lol.

thanks