Slate under speakers?

This is a very interesting thread as I spent last weekend doing a similar project. I too was trying to raise my speakers up a bit to suit there location. I took 1-1/8th MDF I had left over from when I built my house, I spray painted it black and installed adjustable felt feet that I purchased at Home Depot. The felt is very dense and I can now move the speakers by myself which are heavy. My speakers have spiked feet and are sitting directly on the MDF platforms. My floor is porceline tile over concrete slab so it's a very hard surface that the felt feet sit on. To my surprise the base is at least as tight as it was and the sound did improve for me by raising up the speakers.

Got mine on spikes, on top of 1.5 (or maybe 1.25, don't remeber) inch granite slabs (custom cut and polished by a stonemonger down the street), and the slabs each on a trio of those "magic" sliding furniture footers. I've never critically compared alternatives, but figured it's got to be better than sitting directly on a suspended wooden floor and I sure do like the way it looks.

Fishboat. Slate doesn't make sense. You would be better off with less density, surface area etc. Blindjims idea of plywood or even MDF would be much better on carpet. Wrap it with felt to make the wiff happy. The sound will just resonate back through your cabinets if you use slate. It doesn't work.

Donjr

Slate doesn't make sense... The sound will just resonate back through your cabinets if you use slate. It doesn't work.

What is your basis for these statements? Do you have first hand experience or are you just theorizing or imagining what might happen?

In fact, there are sound (pun) reasons for isolation of this type for suspended floors and quite a few AGONers have reported success with this method. It worked extremely well for me and the results were measurable, so I'm concerned your absolute statements might misslead others from trying it.

Zargon. I'm just theorizing. It seems to me that slate or granite would resonate, where as MDF or plywood would not. If I were using slate or granite, I would put it on high density foam and not a lot of it, to cut down on how much surface area is touching the carpet. If you're going from having your speakers spiked to the floor (coupled) to putting them on slate on top of the carpet (decoupled), you will surely notice a difference for the better. Not the best though. You've still got something very heavy and dense, condensing the carpet fibers and slightly coupling itself to the floor, especially because of how much surface area there is with a slab of slate or granite. Companies such as Aurelex have done extensive research on this subject and that's why their line of products for decoupling amps (isolation risers) have very little surface area that touches the floor, yet very large surface area for the amplifier up top. The reason this phenom of slate and granite started was the WAF factor.....really. That's how this all got started. Then everytime somone posted the question, people would reply "I use slabs of granite. It made a big difference and it looks great", and everyone started doing it. I'm not saying it's a bad solution for carpeted floors, but there's better out there IMHO.