Improving a stone rack

I have used Granite for many Years as Sub Plinths for Audio Equipment on Racks and as a Cabinet Speaker Sub Plinth.

I find I prefer the sonic that has been created when using it, when the Granite is a Sub Sub Plinth or a Sandwich Material in a Build up of Materials to create a Plinth or Sub Sub Plinth.

For Speakers I always uses a Spike Coupling and Pneumatic Footer to create some suspension.

On the equipment Rack, I always use Cork as the Isolation footer for the Granite when in a Sandwich or as a Sub Sub Plinth.

Other Materials used in conjunction with the Granite will have  a selection of Footers tried out to discover which tidies up the sonic to a standard I am happy to experience.

Today, my usage of Granite is seemingly being superseded by the use of Phenolic Resin Densified Wood Board Materials, such as the Board Materials from the Brands Permali or Panzerholz.

I recently bought a rack from Acora audio and the shelves are African black granite. The underside of the shelves have some type of anti-resonate material attached to it. I always wanted to upgrade from my 20+ year old Target rack. I was thinking about the aesthetics of the new rack but the improvement in clarity, resolution and musicality has taken my sound up a few levels. I had my doubts about buying a granite rack but when it’s done right, it sounds great. Try reading some info regarding Acora’s racks, you might get some insight on what to try.

Try using a very dense wood that has a totally different sound signature from the hard granite in conjunction with the granite.  I've tried many different types of materials for a rack.  I have been using a pair of Sistrum racks from Star Sound for many years.  Anything that is placed on it immediately sound more live but without ringing or any other sound issue.  I also use RTS couplers to clamp each component to its shelf.  The combo is about twice as effective to improving the SQ as the Sistrum rack alone.  I was very lucky to have a former owner sell me all his Sistrum racks used at very good prices.  You can even install this racks between the speakers with little or no drop in soundstage info.  My two racks are about 18" behind a line between the two speaker fronts.  They allow so much air to circulate w/o ringing vibrations behind heard it's wonderful.  Used they are MUCH MORE affordable.  Thanks Al Jennings.

Bob

“African black granite” is not granite but instead fine grained gabbro. It’s denser than granite, as different minerals make it up. No quartz, and denser, more calcic plagioclase feldspar, and relatively dense, iron rich pyroxene. I am retired now, but I was a volcano guy and used to analyze igneous rocks. Catchy trade name, though. I agree that this material really works for speakers, as all the Acora speakers I have heard are really special. And the owner is a truly nice guy, who I am delighted with for buying Audio Research. 

@jallan I’m not as well versed on granites and types of rocks as you, just going by what I was told. I don’t doubt anything you’ve said. I definitely agree that Valerio Alcora is a very nice guy and great rep for his company. I emailed the company with a question regarding setting up the rack and he actually called me himself and walked me through it. This rack weighs about 250lbs w 5 shelves and definitely improved the sound.