Granite under wood for better isolation?

I went the granite route under my table as well, and then discovered what a mistake it was. Granite rings at fairly high frequencies so you can hear the smearing that results. But it looks wonderful, Dakota Mahogany granite.

I also tried a hard maple shelf before the granite, which was also a mistake with my table. The wood tended to soften attacks so the wood smears in another way.

Best solution I have found so far for my stand and table is to use Stillpoints between the granite and table plinth. The vibrapods would probably work also, but I would suggest listening for any softening in the bass and in attack. I'm not really sure how much they allow movement since I have not used them. I do hear slight loss of bass slam with the Stillpoints, but I can live with that until I find a better solution.

Best of luck. Don't get discouraged, you may have to try several things until you find something that works well for your equipment and tastes.

Put the granite into a sand box. All ringing will be gone.

That is exactly what I have. Unfortunately, it doesn't work. It helps some but the granite still rings. that is why I placed Stillpoints between the granite and my turntable, to isolate the table from the granite.

Tbg, the 1" granite is the shelf on my sandbox and is cut 1/2" smaller than the width and length of the inner sides of the sandbox. There is about 2 1/2 inches of sand under the granite. The ringing can be heard as smearing of detail in the lower midrange. I use the Stillpoints to decouple the table from the granite. It works quite well and also helps provide a very low noise floor. There is a slight softening of bass impact, but that is a trade-off I can live with. I wouldn't say that this will work for all components, but it has worked with my Gavia and stand. The granite is beautiful Dakota Mahogany so that is why it is still there. ;-)

Haven't tried on top of anything, but I have realized the benefit of having weight on some things. Like my speed controller, of all things. :-)

One approach that Thom Makris keeps mentioning is to attach some angle to the bottom of the granite with JB Weld and let the angle embed into the sand. Perhaps more work at getting the vibs down into the sand will make the granite work without the Stillpoints. Something to try this spring.

Again, I have that exact setup with my Gavia and you can definitely hear any rapping on the granite, sandbox, stand, and in one recent case, on the concrete floor. I've now added Stillpoints between my gavia and the granite shelf. I think there is more to this than just the granite on sand. I believe the plinths on Teres and Galibier handle resonances a little differently so that could be contributing to the differences in our results.

Many Galibier owners use aluminum, 3/4-1", as a shelf on a bed of sand with great results. Makes sense since this is what Thom Makris recommends. He also finds that a similar thickness of MDF on sand gets most of the way to the sound with the aluminum. (Me, I went with the granite because of looks alone, so I'm left to compensate with Stillpoints.) It seems to me that experimentation is the only way to know what works. However, I don't know anyone who has a stand that they can rap on an not hear something through the speakers. I really don't think this is an issue because I've heard my turntable with a arm that had a significantly lower noise floor than my Triplanar and this did not reveal any flaws in the playback. Just the opposite in fact. However, on the other hand I would not claim that things are optimal.

Sometimes people get lucky and quickly find something that sounds good to them. I thought I was one of those, but prolonged listening convinced myself otherwise. I will probably build or acquire a different 'table stand at some point to investigate other approaches.