you can still use granite or marble, just not by itself-glue with tile mastic to 3/4 mdf use a 1/4 x1/4 notch trowel and trim the sides with wood.
i did this the mastic grabs the vibrations before the granite or marble have a chance to ring.you can do the tap test to see the difference.
i've also used mastic inside speakers, works nice.
i did a top for my sub this way to add weight, liked it so much i did the sides of my diy speakers also.
if you want to do it , get 12x12 granite or marble at hd and get the pieces cut to size(split the center of shelf-4pcs per shelf at 4-10$ a piece),glue to the mdf and trim with maple or oak and grout (the solid 3/4x2 xlf stuff)use the same maple or oak for the 3 legs, use brass screws thru the sides of the legs into the shelf pieces.
has the mission furniture look.
wont cost 1/4-1/3 of what that one costs.
heck if you live in upstate ny let me know i do tile for a living and i'll make you one.
