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

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

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

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

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.

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!