what is the theory behind maple stands and racks?

Mapleshade claims they have done comparison tests and have found that North American Maple "sounds the best". They are in the business of selling the stuff, so I take their claims about maple with a pinch of saw dust. Who knows - maybe a little bit of the right kind of "sustain" in your platform makes your audio gear "sing" like a stratocaster?

In my limited fooling around with different isolation platforms, I cannot tell the difference in sound between Maple, Ash or Bamboo. BUT I find that I can tell the difference between intact wood and MDF, particle board, synthetic materials or steel (although Aluminum may be a good choice), with wood sounding the best to me. And the thicker and heavier the wood the better.

I can see it now - knownothing's Genuine North American Tree Stump Equipment Stands...

Any fans of granite shelves?

Magfan, I used a 1.5" exotic granite slab under my TEAC Esoteric X-01 Ltd CDp for a while. . . In my opinion it hardened the sound. At the time I 'solved' the problem by interposing a $15 IKEA square stool top between the 2. But now the pretty granite has been relegated to end-table-top duties in the living room, and I have the CDp on top of a 50 year old 42"x22"x2" slab of solid african Mansogna wood. . . it does not seem to impart the system bizarre resonances. Some rack makers do use granite, but often not by itself. E.G. HRS does not use pure granite shelves. . . but uses granite as the top layer of composite shelves. G.

thanks for the interesting reponses. It appears that maple may be worth experimenting with. It is mysterious, or at least, not clear to me, how the coupling/draining vibration thing works, but that it can audibly improve things I have no doubt. There seems to be some combination of equipment coupling, vibration draining and isolation that works, but it appears to be difficult to predict how or why or what works. For example, I tried putting my amp (large tube amp, has large rubber=type feet) on spikes (i.e., instead of the "rubber" feet), on a white acrylic cutting board, sitting directly on the floor - poor result. Then tried the amp on the cutting board which was sitting on spikes, on the floor - excellent result (at least as good as a Billy Bags amp stand, which is, in a way, a similar combination of an inert shelf supported on steel coupled to the floor.)

Interesting - I had a similar result with solid state amp. Wooden platform had almost no impact on sound. Wooden blocks in place of amps rubber feet and placed on polyethylene board = little but slightly less appealing effect. Amp's rubber feet directly on poly board with the board on metal blocks on shelf - slightly better.

For all other applications (speakers, CDP, TT) I use wood - maple, ash and bamboo. The applications of these materials are driven more by cost, size available and aesthetics of a each piece, rather than focusing on the particular variety for given use. As long as the wood is fairly hard, it seems to work pretty well, again the thicker the better. Someday I may get around to doing an independent test of Mapleshade's claims for NA maple.

On a related note, I have tried Sorbothane dots directly under my gear, and used it to isolate shelves from stands and heavy wooden platforms from shelves. In these applications, I was not happy using the material to decouple equipment from whatever is directly supporting it as it seems to suck some of the life out of the sound. But I am happy using this material to decouple the platform from the shelf, or the shelf from the rack (can play system louder through room speakers before compression or distortion sets in).

This leads me to believe the purpose of the wooden platform is to drain INTERNALLY generated vibration away from your gear, while the purpose of an elastic material like Sorbothane is to decouple or isolate your gear from room vibrations originating from your speakers and transmitted to your gear through your rack. I say this because the benefits of the wooden platforms and anything you put between the platform and your TT or CDP (e.g. wood or metal blocks, cones, Sorbothane, etc.) are clearly apparent even when using headphones, and so must be interacting directly with the gear irrespective of room vibrations.

Finally, for your tube amp, I would think the platform material is a more critical factor than it seems to be for my SS rig. Since tube amps generally have big transformers, they can generate a significant amount of vibration on their own, and since the tubes can be affected by both internal and external vibration, I would also experiment with heavy wooden platforms and spikes/cones/Sorbothane as well for that application.