Coulomb friction is a simplified quantification of the friction force that exists between two dry surfaces in contact with each other. All friction calculations are approximations, and this measurement, which was developed in 1785 by Charles-Augustin de Coulomb as a refinement of Leonardo da Vinci's classical model, is dependent only on the fundamental principles of motion. It assumes that the contact surfaces are fairly uniform and that the coefficient of friction that must be overcome for motion to begin is well-established for the materials in contact. It also accounts for the normal force involving gravitational pull, whether in direct horizontal movement to the normal force or at a vectored incline.

LOL, just read an interesting paper from Star Sound Technologies on the subject and how it applies specifically to audio and video equipment here.

Yes, they have a horse in the race with a technology they developed called Live-Vibe Technology that provide high-speed channels for vibrating resonant energy to locate earth's ground.  None the less very interesting read.

Simply stated, if the vibration is not directed away from the source, it will modulate the source causing the original signal to appear distorted, thus defining the requirement for continuous dissipation of vibration.

Employing isolation techniques, one merely protects one component from interfering with another that it is in direct contact with. Isolation increases the effects of Coulomb friction by building resistance between the mating surfaces. With regards to airborne resonance, isolation principles serve much like the dielectric material in a capacitance device, essentially turning the component into a giant Resonance Capacitor.


What does it all mean?  Their theory is ... since musical instruments resonate to make their sounds, it is better to keep the sound "live" and transfer resonance of the reproducing system as quickly as possible to earth's ground through special vibration methods rather than "deadening" the sound through dampening, absorption and isolation which would be unnatural.  IMO it makes a lot of sense.

What do you guys think?

seikosha beat me to it. This all sounds familiar.

I wish I had a good lab grade accelerometer so I could test damping materials and platforms. I grew up with the theory that you drain the vibrations down to the floor, so it was weird for me to see everyone using maple platforms and brass/sorbithane/magic to absorb/damp vibrations.

Since I don't have fancy testing equipment, I'll just have to use my ears and do some experimenting.

I'm currently working on a 4' tall gear rack that's heavy extruded aluminum legs that will probably be sand filled once I get it into place. And I'm experimenting with different shelf materials. I've already got a 2" maple deck, and a plywood/mdf deck, and I'm working on cutting out a plywood/MDF deck that's lead pellet filled, and one final deck that will be a sand box with plywood or MDF "floating" in the sand. I figure I'll move the amp around till I figure out which deck sounds best, then do the same for my DirectStream, then the PC. If one material sounds best, I'll rebuild the whole rack using just that type of deck.







If anyone has any idea how I can actually measure the vibrations/damping, I'd love to hear about it!

The problem with isolation, is that the devices themselves resonate.

I think that there is a fundamental difference between an amplifier and a musical instrument (I did not advocate isolating speakers).  I don't see any benefit in my amplifiers vibrating.  My point is that rather than stop the vibration after it has begun that it not be allowed to vibrate in the first place.  We want to make music with an instrument so obviously vibration is necessary with that.  Apples and oranges. Or am I  missing something here?  I guess that I wasted my Masters Degree afterall.  My Mother will be very disapointed!

My approach to isolation was to build a simple platform that acts as a vibration filter.  It may be counter intuitive but my amplifiers sit on springs.  The springs have a natural frequency well below the audible range -- say 10 Hz.  Higher frequencies than that can't pass through the platforms into the amps.  Of course, there my be sublte vibrations but they are many times less than the vibrations coming from the stand.  In fact, when I first set up my ZMA, as sent from Decware, I actually got horendous feedback at high volume.  Once I placed it on the platform any sign of feedback was eliminated.  My turntable has it's own isolation feet and I can pound on the shelf that it sits on and get no audible respose through the TT.  

I think that if vibration is not desireable in a component then it is always best to filter it out rather than attenuate it later.  As far as I know there is only isolation and/or damping (friction into heat) to deal with vibration.  Anything else is Voodoo magic.  Once vibration gets into a component, some "damage" is already done.