okay, given the lack of shun mook-ers on this site, this takes some courage, but here it goes: i experimented with brightstar big rocks, corian (sorry, misspelled) and marble. the marble may have been the best in terms of tightening the image. then i talked to bill ying at shun mook. he suggested making my own sand box from u.s. maple wood (kind of like a "natural" brightstar). failing that he suggested i use a u.s. maple cutting block. i tired the cutting block with some cones beneth it and found i liked it better than the marble. the image was just as tight but the warmth of my (tube) amps came through moreso then when they sat atop the marble. as always, its a matter of personal preference. good luck.