Sorbathane under granite slabs for speaker bases?

asahitoro - sorbothane is a tricky material to use. One might think more is better, but my own experience leads me to believe less provides greater benefit.

I use it throughout my system between the feet and the components.

As an example -  My turntable was sounding great with 1/10" sorbothane on the feet, so I thought I'd try two pieces of 1/8". The result was terrible - the dynamics dropped off and the bass became bloated.

I'd opt for 1/10" sorbothane in your case and even then - I'd put a small 2x2 inch piece at the corners and one piece in the middle

I also spoke to an HVAC installer that uses it to curb vibrations and he said using strategically placed smaller pieces is often more effective.

Regards

According to sorbothane’s own site this material dampens vibrations by transforming them to heat. This is basically the "conservation of energy principle." Earlier above someone stated that it just stores energy, but that is not what it tries to do. Its damping comes about because of the transformation to heat.

I have used sorbothane footers for many years but have got far more effective results simply by attaching small pieces of it using the self-stick tape which it can be bought with, or other adhesives. I recommend Lord 7650 a fairly expensive industrial adhesive if you can’t get self-stick I have applied this on turntables amps, transformers and the like with excellent results.

However sorb comes in several grades and sizes. The best results for audio come with the more dense product, 70 duro is about the densest you can get. Also use the thickest you can get. I am using 1/2 inch where I can. It is certainly very effective attached to the front panel of my speakers. It is better to have some form of backing or clamping to the sorb but it is still surprisingly effective (after the adhesive or self-stick dries) just stuck in place, I generally apply two layers of electrical tape to the back to make what I believe is referred to as "constrained damping."

I got into this area when I realized that headphones had major damping issues. They all buzz around because the vibrations in the earcups are neither effectively damped nor able to drain away. So I and others have been sticking sorb inside earcups, on headband and the like.

I was surprised to discover the Sennheiser had already been doing this by installing what it variously terms"space-age material" or "polymer" to the headband of its previous TOL HD800. I would imagine they also do this with their current ultra expensive electrostatic but I haven’t seen anything from them saying this. It could just be that they are using sorb which is also a polymer, but there are other materials now with such damping properties. Grado is using a "proprietary polycarbonate" in its new e-series phones to obtain better damping.

The other dirty secret about vibrational problems in headphones is that there is quite a lot of mechanical cross-talk going on across the headband. That is why the Sennheiser HD 800 works with the damping material in the headband. I have found this to be true in various Stax phones as well. However, I prefer to start the damping right in the earcups where possible, but I am adding it to the headbands as well.

I have been running a couple of threads, mostly dealing with headphone damping, eg. http://www.head-fi.org/t/744839/damping-mechanical-energy-distortion-of-stax-and-other-phones-with-s...

Please don't listen to me get granite and enjoy!!!!!

Well, transforming vibration to heat is what ANY constrained layer viscoelastic type damper does, but Sorbothane is not as good at this as many other materials for whatever set of reasons. Any major dude will tell you. Certainly Sorbothane doesn’t isolate down to 5 Hz. That’s hooey. In the overall scale of things I’m inclined to say Sorbothane is one of those materials a lot like lead that appears to be a good idea but in practice actually hurts the sound. Great for running shoes, though.

Sorbothane, or any elastic substance will allow the speaker to move - esp. when a bass note at high volume is sounded.  This is a no-no in any box speaker, as that will phase-modulate all of the sound.

If you have box speakers, you want spikes.