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.)
what is the theory behind maple stands and racks?
I have not "heard" a maple amp stand or rack - using Billy Bags products now, which are made from steel and mdf - but don't grasp why maple would be a good material to use - quite the opposite. Maple is used for some electric guitars because it "rings" - it is very dense and causes notes to sustain, which is to say, it continues to vibrate for a long time. This would seem to be exactly the opposite of what one wants in a stand or a rack. If there is some claim that vibration is "drained away", well, if the rack is continuing to ring, that would likely cause acoustical feedback - the equipment isn't isolated from the thing it is sitting on. Can anyone who is not a vendor of these things explain the why of it, or relate positive experiences that seem to have a basis in fact?