2" maple shelf or 3" one:sound different?

Im sure you will get posts that say, sure, bigger shelves sound better. I for one can't imagine it would make any difference...maybe if you have a $50K system. Good luck!

When I replaced the 1 3/4" thick maple platform under my VPI Scout with a 3" thick one, there was an improvement. It was not nearly the order of magnitude of improvement that I got going from no platform to the thinner platform though. My listening room has carpet over a concrete slab floor, so there are no issues with floor vbration. If you've got vibration issues, there might be more improvements with the thicker version.

I forgot to ask which grain though:edge or flat one?

One time I used a heavy piece of wood furniture instead of my audiophile stand with MDF, and I found the system was just damn sluggish until months later I put back the audiophile stand. My room is VERY damped though (carpet, curtains, sofa, etc.).

I find the results of tweeks to be often counter-intuitive, can't tell until you try, alas.

Art

The resonant frequency of the boards is the same, but a vibration will have to be stronger to get through a 3" than a 2" board.

I have used stands with MDF shelves. It worked just okay, then I changed to 2" maple, there was an improvement, then I changed to 3", and again it was a little better. THEN I changed to a Sistrum all metal rack and have never looked back. It was better in every way...

I know there are better racks, but they cost a lot more, I'm trying to squeeze out the most music for the least amount of money... call me cheap, or call me Ahab...

:o