I use a inch and a half thick slab of black granite under my floorstanding speakers. The speakers have cones and feet protectors which I purchased from Adona, sitting on top of the granite. As the speakers weigh 85 pounds each, they are extremely stable. In my case, It made a tremendous difference over just having the sharp cones going through the carpet to the wood floor below. Bass impact is much better now with no smearing and everything seems more defined. I am currently using Odyssey Kismet Reference speakers and also used this combination on a pair of DeVore Gibbon 8 speakers a few years ago. The results were pretty much the same.
I will say that the cost of the granite was a bit pricey, I believe I paid around 100.00 for a pair of 10" by 14" pieces 1 1/2 inches thick, polished on all edges as well as the top.
I will say that the cost of the granite was a bit pricey, I believe I paid around 100.00 for a pair of 10" by 14" pieces 1 1/2 inches thick, polished on all edges as well as the top.