Where does one place AQ sorbogel feet?


I got 3 AQ sorbogel Big feet. These are supposed to reduce mechanical vibration by absorbing energy and releasing it as negligable heat. My question is where under the cdp or amp do I put them. Everyone seems to use them in threes and there are 4 feet. Do I place 2 on the insides of the front feet and 1 between the back feet? Does the flat side face down or up? What do I use to protect cdp and contact points (theyre sticky)? Anyone have experience with these and how do they sound? Thanks in advance!
bundee1
Now you have 2 positions to trap the noise,top and bottom. No exit to escape from..
Theaudiotweak wrote, "Dampening devices are not selective to the frequencies they alter nor the dynamic structure they alter."

This is untrue. All dampening devices affect some frequencies more than others. To expect otherwise would be to expect a material to react identically to differing energy inputs, which is clearly impossible. Sorbothane's website has detailed and specific data on the quite frequency-dependent effects of different sizes, shapes and durometers.

That said, Sorbothane can certainly cause problems as well as solve them. Using the appropriate Sorbothane product beneath the feet of my A/V cabinet yielded significant audible benefits with no downside. That tweak was an easy keeper, as were the four Sorbogel feet beneath my turntable. OTOH, Sorbothane feet beneath my speakers (B&W N803 on a carpeted wood floor) were an instant music-killer. Took those things out of there and put 'em back in the drawer.

Like all tweaks, listen with care and don't be afraid to give them up if they don't work.
Dougdeacon, Sorbothane is a frequency absorber and a damper. Which selected mechanical frequency did you choose to alter that did not change the frequency before or after the fundamental? By changing the Q did you not squelch the dynamic structure? All dampening devices are also storage devices. So how much was absorbed and how are you to predict the time and selective frequency to be released?
Theaudiotweak: sorry if I wasn't clear. I did not mean that Sorbothane doesn't react to/affect all frequencies. Clearly it must, but it reacts to/affects them differently. Sorbothane absorbs higher frequencies more than lower frequencies. As a result, it lowers the overall system resonance frequency. How a Sorbothane-floated system responds to vibration depends on the frequency of that vibration.

Sorbothane lowers a system's resonance frequency by absorbing vibrations above that frequency. The farther above the system resonance frequency an incoming vibration is, the more of it will be absorbed. This absorbed vibration is largely converted to heat, *not* released later as vibration.

OTOH, Sorbothane tends not to absorb vibrational energy below the system resonance frequency. At those frequencies, it seems to act less like a damper and more like a coupling device.

If you want to lower the natural resonance frequency of a system, (ie, to reduce exposure to support-borne vibrations above that frequency) then the appropriate Sorbothane feet should have reasonably predictable results. This is what I wanted to do with my equipment rack, which is sitting on a suspended wood floor that is easily excited by my speakers. Floating the rack on Sorbothane yielded greater clarity, faster attacks and a quieter background at all frequencies above 30 Hz or so. Frequencies below that, as best I can tell, are slightly amplified but seem about as clear as before. This is consistent with the worksheet on Sorbothane's website, which calculated that I'd have a system resonance frequency of about 28 Hz.

If, OTOH, a component is intended to be *producing* multi-frequency vibrations, as a loudspeaker is, we would predict that placing any vibration damper beneath it would impair its performance. That was exactly my experience with Sorbothane beneath our floorstanders. Attacks were severely dulled. Very bad.

Sorry to Bundeel for highjacking his thread with such a lengthy post. Enjoy the music!