Sorbathane under granite slabs for speaker bases?

At one time, I had a pair of floor standing speakers on a 1 inch thick slab of black granite.  It not only tightened up the bass, but removed a slight smear in the midrange.  I placed them directly on the carpet with the speakers with spikes installed on top.  I used the cups for the spikes to fit into. 

Send a message to Robert @ Herbie's with your specific question, he will get back to you quickly.

My floors are raised wood. I  had a hell of a time getting the speakers to sound right.

 I tried just spiking them through the carpet and into the wood floors. Undefined  bass. 

Then I tried them spiked to granite bases.  Improved mids and highs. No bass. 

Finally, I bought a pair of Maple Shade unfinished maple platforms. I spiked the platforms to the floor through the carpet, then spiked the speakers to the maple platforms. Walla! Done. 

Double click on my icon, then double click again to see the Maple platforms under the speakers. 

Frank

agree with Mapleshade, avoid granite

The very expensive TMC isolation platform uses a thick granite top plate. I have used thick granite and bluestone with springs, sonically exceptional in every way. High stiffness and high mass on springs, cannot beat with stick. Granite cannot ring when it's isolated. Hel-loo!