Sorbathane under granite slabs for speaker bases?

I guess the question is whether to drain or isolate.  Personally, I've avoided visco-elastic stuff under speakers.   Expect others have opposite experience to share.

I'm using hardwood (3"?) plinths directly under speakers.  Hardwood resting on large 18x18" tile.  Tile on carpet.  The tile gives the plinth stability on the carpet.  The hardwood "drains" vibrational energy from the speakers (or so I think). 

Thanks ghost,

Are you using spikes as well? I think I'm going to roll with just the granite slabs directly on the tile shelf w/spikes under the KEFs.

Always good to experiment, ahahitoro.  Plain granite now doesn't eliminate the possibility of later trying some wood in between.  

To answer your question...yes, I use the spikes as well.  With the Silverline Preludes, I use the spikes they supply though have installed those little dimpled discs to keep the spike from digging into the wood.  With the Forests, they have a "ball & claw" arrangement for coupling.  The balls rest directly on the wood.

Well, I have a thoery that works for me. How you implement it is up to you.

1. Minimize surface area contact with floor, furniture, etc.
2. Minimize opportunity for speaker to move, often by adding mass.

The reactive force of the woofer motor can cause enough motion to distort the sound, or vibrate against the floor, Minimize that by any means necessary.

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.