Component isolation


Let’s say you’re going to add isolation feet to a component with no moving parts, such as a preamp, phono stage, DAC, amp, tuner, etc. 

Which one is most critical to the extent would get your attention first? 
zavato

Showing 5 responses by bdp24

I have roller bearings by both Ingress Engineering and Symposium Acoustics, as well as Townshend Audio Seismic Pods. Roller bearings provide good isolation in all planes but vertical, in which they act as not isolators, but couplers. The Seismic Pods are very effective in all planes, a great product imo. Available in many load-specific versions, around $100/pod.

Doug Sax had the best method of determining the transparency of any given piece of equipment---the bypass test. He would compare a live feed from his studio with the sound of the same signal passing through the device being evaluated. Any difference between the sound of the two was the component adding it’s own sound to the signal---aka distortion. The idea of high fidelity is to minimize that difference. Hi-fi components aren’t musical instruments, they reproduce them. The sound of musical instruments and voices contain timbres and textures; a hi-fi system should have none of it’s own. In fact, the less it has, the better able is it to reproduce that of instruments and voices.

It’s a very old dilemma: Do you want your system to reproduce the sound contained in recordings---whatever that sound may be, or do you want it to create sound you "like", regardless of the sound contained in recordings? J. Gordon Holt, the pioneer of subjective reviewing, argued for the former and against the latter. Harry Pearson’s standard was what he called, as we all know, the absolute sound---the sound of acoustic instruments in a real space, like a concert hall, cathedral, or even recording studio. But that construct relies upon the assumption of recordings containing such sound, waiting only for it to be reproduced. Very few recordings contain pure acoustic sound in a real space (in Pop music, virtually none do), yet Harry and his believers continue(d) to evaluate components based on their ability to create sound like that heard in those real spaces.

That is not so different from Amar Bose designing a loudspeaker that mimicked the 11% direct / 89% reflected sound heard in concert halls. That is imo an inherently flawed concept (recordings made in those spaces contain the direct and reflected sound; to play them back on the Bose 901 doubles the effect. For Bose’s concept to work, recordings would need to be made in an anechoic chamber). So imo is the notion of a hi-fi system itself being approached as a musical instrument, "tuned" to one’s liking. Minimizing the sound added by the system, on the other hand, is a noble pursuit. A hi-fi system (and perhaps I ;-) should not editorialize. The sound of the listening room is itself, of course, part of the system. Perhaps the largest part, along with the recordings. Minimizing the deleterious contributions of the listening room is imo the biggest challenge facing music listeners.

Guitarists who play in more than one tuning often have multiple guitars on stage, one (or more) for each tuning. They don’t play one guitar, retuning it for different songs. I find it hard to believe many here have any desire to re-"tune" their system for each recording they want to listen to. Am I mistaken? Don’t most of us want a system that makes ALL recordings sound as much like what we think music does (or perhaps should)?

Good questions and comments Terry. Damping the vibrations in a component, vibrations that the component may potentially add to the signal, is not "dampening (sic) part of the audio signal." Where in hell did THAT idea come from?! This idea that components themselves should be considered musical instruments, free to resonate, is SUCH an anti-high fidelity concept. Components should simply reproduce the sound of instruments (and voices) contained in recordings, having or adding no sound of their own. My God, that’s the first truth of hi-fi!

"Low mass frees the sound" and "High mass squeezes the sound" are just overly-simplistic bumper sticker slogans. Audio engineers don’t think in those terms. The high-mass VPI turntable platters (the purely stainless steel, the stainless steel/Delrin, and the aluminum/lead/Delrin) sound MUCH better than the low-mass acrylic platters. My Townshend Audio Elite Rock table has a plinth of a metal frame filled with bitumen pads and plaster-of-Paris, built that way so as to be non-resonant. Designer/engineer Frank Van Alstine suggests lining the inside surfaces of the wood bases of suspended subchassis designs (Linn Sondek, Acoustic Research, etc.) with modeling clay for the same reason. If high mass achieves low resonance, that’s a good thing. Of course, that too is an over-simplification, as there is the matter of resonant frequency, Q factor, etc.

Frank Van Alstine was recommending a paving stone sitting on an under-inflated inner tube as a turntable isolation platform way back in the mid-80’s. I believe the idea was already very old even then, dating back to the 1950’s. The early, WWII-generation engineers and audiophiles got a lot right.
Isolation need not involve damping or lack thereof. The Townshend Audio Seismic products and the IsoAcoustic GAIA's provide isolation only.