Vibration Isolation for equipment using granite?

A cure looking for a disease? 

See here and here

Mike

Sound transmits better as the density of the molecules of the medium it is traveling through go up.  Hence sound travels through water more efficiently than through air, and logically through solids more efficiently than through water.  That is basic physics.  Any mechanic can tell you that using a long handled screw driver, handle against ear, blade against malfunctioning mechanical noise (such as failing bearing), is very helpful in isolating the location of a problem on an engine for example.  Yes he/she can hear the knock, but locating which bearing is failing that is harder.  So, back to the granite blocks, are they solid?  As such and understanding physics, do you think they would be effective acoustic isolation barriers?

I would say neither true, nor snake oil. I use granite slabs under my amps and under one of my turntables. I find a subjective improvement in quietness and contrast on these. But I would say, as with so many things in the sport, a try and see kind of thing. We all hear a bit differently.

I try to avoid speculative theory, but I believe the primary resonance frequency of the support is more important than the speed of propagation in the material. And this particularly true in turntables where the suspensions are tuned to different frequencies.

One must be careful when using granite or other solid rock. They ring and they transmit energy through them very efficiently. So you would not want to use cones under a granite slab on a concrete floor. You would be transmitting the energy directly to the components. 

On the other hand, the mass is an advantage. So, to get the value without transmitting vibrations the slab needs to be isolated. So for instance elastomer pucks or Vibrapods under can isolate them from small vibrations. For my amp, I use an amp stand, with vibrapods on top of it, then the granite slab and springs on top of the granite. Mass works to my advantage here. 

But even better, as I use under most of my components are vibrapods on the rack shelf, then Black Diamond Racing platforms (very dense composite... really heavy), then springs on top of that, then component. This is a fairly slim profile.  

For my turntable I use a custom Silent Running Audio Ohio Class vibration platform. These guys make vibration platforms for electron microscopes and other really critical applications. It had a very significant effect on my Linn, Klimax turn table. I would say this is the highest level of vibration control, Townshend platforms are also transformative for speakers.