bossobass,

Your granite "sink hole" solution is exactly what I have advocated in other threads for use under turntables.

However one thing to note about this approach: you need BOTH mass (granite) and an acoustic insulator for it to work properly. I suggest two slabs of granite sandwiching a layer of rubber. Those non slip workshop mats (that come in rolls) work well. Just fold it to get four layers. You can even sit the speaker on another layer of mats (both for additional isolation and to keep the speaker from "dancing" on the polished granite.

Regards.

Jeff Mackwood