i have found that hard objects tend to enhance resolution, while softer objects, such as foam, and sorbethane tend to soften the sound.
there is another material, i believe it is called blu tack which when placed under a small speaker may reduce cabinet colorations, without creating the above mentioned effects. blu tack is a light sticky substance, reminds me of silly putty.
as to materials under the stand, hard objects are usually used, to treat problems in the bass. you may also want to weigh down the sands by adding sand or lead shot.
there is another material, i believe it is called blu tack which when placed under a small speaker may reduce cabinet colorations, without creating the above mentioned effects. blu tack is a light sticky substance, reminds me of silly putty.
as to materials under the stand, hard objects are usually used, to treat problems in the bass. you may also want to weigh down the sands by adding sand or lead shot.