help on isolation/absorption/coupling

Stereophile had a collection of tweaks compiled from JS's Fine Tunes. It is probably on their site. I my have it around and can get it to you if you would email me.

Wtsaila: I have the same type of amp setup as you and can warn of one thing. I tried placing brass cones under my Audion amp (which sounded good) however they also stored a lot of the heat coming off the chassis which after an hours play was like having the amp resting on three hot coals (not a good thing). I guess that you could say that they were drawing heat from the chassis, but they were also introducing it back into the amp, as well as raising the amount of ambient heat. I temporarily settled for resting the amp (on its stock feet) on a maple board supported by Vibrapods, but will soon try out Neuance shelving (again just using the stock feet on the unit).

Wtsaila this is a very confusing area. Alot of terms that I don't understand, so if your new it must be very confusing. I would like you to read the post "Footers/Shelf Material" first. Redkiwi does a good job outlining the basics. After that if you want further help please e-mail me or Redkiwi and we would love to help further. Redkiwi is the most informed I've read here, and I know he'ld be honored to help you. J.D.

If you have old Stereophiles, the November, 1995, article by Shannon Dickson on vibration control must be considered a classic. He reviews the Townshend Seismic Sink and the Vibraplane platform in the same issue, and all of this makes very revealing reading. One general idea is that cones )or tiptoes) and pucks (elastomers) tune resonances rather than eliminating them--move them around to a place possibly more to your taste, and nothing wrong with that, but by no means a genuine elimination of resonances. It's a discouraging article, for people hoping for a relatively cheap way to get in good shape vibrationwise. But best to know the truth.

The whole concept of Isolate/absorb/couple really comes down to isolating vibrations and de-coupling them from the problem area. What that means is that for speakers you would like to isolate (for example) cabinet vibrations generated by the speaker itself and then decouple it from the speaker movement. For a CD or other source device you would like to isolate any external vibrations from it. Even amplifiers have both internal driven vibrations and external ones. The transformers within an amplifier will generate a certain amount of internal vibration. You would like to disipate this vibration without creating new vibrations. This is where things get complicated. For speakers usually spikes work--why?? Well They effectively couple the speaker to the floor, thereby using the weight and the rigidity of the speaker to reduce vibrations. Secondly the spikes will disipate some internal vibrations into the floor. For source material this can also work, but because of the lighter weight and the fact that most of the vibrations are external, things such as vibropods work very well. They reduce external vibrations from travelling into the source. Lastly would be amplifiers--these can be more complicated. They are susceptible to both internal and external vibrations and are typically heavy (large class A type). For these I've used marbles in a home made fashion likey the symposium roller blocks. This disipates the internal vibration, gives rigid coupling --to use the mass against external vibrations.

In the end all of my comments are general. Like many things in this hobby--you can try the theory and it may or may not work for you. Some people have found vibrapods under speakers to work and cones under source equipment to work. Your ears are really the final judge--but I hope I've given you enough to start tweaking in this area.

Hi, I agree with all the above comments. To give you a background I have experience using different kinds of accessories including brass cones, Black Diamond Racing, Sorbothane, vibrapods and spikes for speakers. Having reviewed the articles above and extensive surfing I can conclude that a lot depends on your own equipment and there are a lot of misleading claims out there.
However I do believe that Black Diamond Racing, air isolation (Townshend, Vibraplane & Brightstar) and a new product called the Vistek MIB are the most effective.
Let me elaborate on the last. There are at present four reviews concerning the above and three of them are found in www.mediaaccess.com. The last is found as a sidetopic in Robert Deutsch review of the Wavelength amp in Stereophile May 2001. If you read into each review with a critical eye
all of them are enthusiastic about these items. I think most reviews to some extend are not objective to avoid offending manufacturers. However read the above articles and see whether you can detect the reviewers geniune praise
and the sound scientific basis of these accessories.
As for me I am convinced. The netsite also compared MIB's with an air isolation platform. Have fun!

Thank you everyone for your helpful answers.

My experience in this area is limited, but clear: the use of a Neuance isolation platform under my CDP resulted in considerably better coherence, and integration of top octave info, WITHOUT the lower-freq rhythmic compromise of air bladders or sorbothane; the success is sufficient to allow my continued use of very revealing interconnects on most good recordings
(although I'm still seeking a les-revealing cable for too-bright CDs). I had almost given up on Redbook! Good luck.
Ernie

don't make things more complex or expensive than they must be. if you have a cheap rack (non filled support beams, glass shelves, etc), use an inner tube b/w your shelf & your component (kids bike 12" works great). this is to remove floor borne vibration from the equation. now what remains is internal vibration from the component. heavy weights on the top or damping sheets inside the chassis works well, some cones as feet work well. try & see. by & large, the floor borne are more difficult / more prominent, that is, unless you have a great rack...and few people do.
rhyno