Wood blocks underneath components?? snake oil?

Dumb question time for all you resonance control affictionados....

Its my understanding that everything resonanates at some frequency. By using different materiels aren't you just changing the resonance frequency? Wouldn't you need to know the frequency at which your present system was resonanating in order to select a materiel to move the resonance frequency to a frequency where it becomes less of a problem (I would guess that frequency would be one which was not being excited by other stuff in your system or room)?

Help me to understand this.

Thanks........

The last time I replied to a similar post it never made it past the moderators for some reason. Placing different materials like wood or brass under a cd player or tube equipment will alter the sound slightly at times for better or worse but are not very effective in isolating the component from the mechanical vibrations via the rack. If you look up isolation or vibration damping devices you will find that materials like polyurethane are used often. Sorbothane is just ultra soft polyurethane. As a mechanical engineer with access to vibration analysers it is easy for me to see which materials dampen vibrations and which don't but I doubt I can convince any of the serious audiophiles to give up their high dollar cones and ball bearings for something that cost a few bucks.

Rotarius...could you please elaberate...

Are you saying sorbothane, which most of my equipment came with and which it still sits on, is one of the better vibration damping materials? Is there something better in the polyurethane family, or are you refering to another material?

Please share with us, the benefit of your knowledge

Or suffer yourself and plow through the article, it's heavy reading:
[/url=http://stereophile.com/reference/52/]bad vibes[/url]

Newbee, I don't think ceramic stone has a resonance, I could be wrong though :-).

Rotarious, question is do you prefer to isolate, transmit, or dampen vibration. Are you pushing the air bladder concept? Check out the bad vibes article, you can't eliminate the vibes. Here are some excerpts:

"The best vibration performance you can achieve is nearly 100% transmission of floor-borne vibrations through the platform without amplifying them or generating and new resonances in floor OR platform"

"Transmitting nearly all of the floor vibrations to a component. . . would be a significant accomplishment compared to most real-world coupling schemes"

C'mon guys read it your yourself.

Cdc, FWIW my question is probably not relevant as I was mixing apples and oranges so to speak, i.e. vibrations control vs resonance control, but FWIW yes ceramics do have a resonance point.

Best example I can think of which graphically show this is the old Memorex commencial showing the glass (similar to ceramics) being shattered by a singers voice (with out regard to whether or not it was actually Ella's voice that did it). It isn't so much as whether or not ceramics have a resonance point, it is what will the substance do when it's resonance point is reached. Depending on the amplitude of the sound at the resonance point of the glass it will ring, ring excessively, then shatter if the signal is strong enuf. If the resonance frequency is high enuf you won't hear the ringing - you will just see the shattering. (But your dog will be hiding in the bath tub!)

As a pratical matter in audio usually all that will happen is that at the resonance point there will be a peak in frequency at the point of the resonance, which you may or may not hear depending on its amplitude. Think of wood speaker cabinet resonances and how, or whether they are damped by the manufacturer and how their existence affects the sound. Also as excessive high frequencies can cause glass to ring I would imaging that would be one of the contributors to the level of microphonics we hear in tubes, thus the application of damping rings to damp the vibrations. Thus the purpose of damping rings applied to tubes. Just a guess of course.

What I was trying to figure out in my question was do we factor into our consideration of vibration control (products & application) the resonance points of the products themselves and how this might interact with the resonance points of the products we are trying to control, or are we simply dealing with either a broad based vibration damper (such as a soft rubber type product) or narrow based product used to facilitate the transmission of a narrow band of frequencies, such as metal or glass (ceramics).

I wonder if a lot of the differences that folks attach to the different vibration control products have any relationship to their ability to control (damp) the resonance points of the audio equipment that they are using.

I've asked this question before and have never gotten a response. Perhaps I'm just whacked out on this and there is no basis for a question, let alone an intelligent answer.