Scientists vs Audiophiles 1999 More Letters part 2

The conclusion is that, at low gains, audiophile-reviled op-amps like the NE5532 can achieve almost perfect audible transparency at low gains because their nonlinear distortion residual is below the unmasked threshold of hearing up to a listening level of 105dB or so. Their linear error is adequately represented by a first-order RC rolloff, which is high enough to ensure that the error is almost entirely a frequency-dependent phase shift. In turn, this phase shift represents almost constant group delay throughout the audible range, and is thus almost entirely a benign time delay. These results are comforting because they tend to verify conventional negative-feedback theory, another bone of contention in audiophileland.

It is both instructive and dramatic to listen to the residual. When the input is not connected to the null point, one hears only the output, which is purposely turned up to be very loud. When the input is connected to complete the null, the result is dead silence. If one puts one's ear right to the tweeter, it is sometimes possible to hear the slightest ghostly whisper, representing the linear residual at very high frequencies. This puts to rest any fantasy that a "cheap" op-amp cannot be transparent. I am convinced, however, that if the price of the NE5532 were to return to $6 (which it was, more or less, when it was first introduced in the '70s), it would suddenly sound much better. (As you may recall, Bob Carver is something of an artist with this technique, manipulating the residual to simulate the sound of different, purposely colored audiophile amplifiers.)

To summarize my point: Experiments, properly done, are crucial to progress in engineering. But audiophiles (in the sense that Reisch uses the term) are, in fact, the anti-experimentalists, rejecting the results of any (blind) experiments that conflict with their worldview, regardless of overwhelming evidence of the efficacy of blind experiments developed from experience in professional practice. I think that some of the antipathy that pros have for "audiophiles" is that, ultimately, pros have to make things work and to please their clients, while audiophiles are required only to please themselves—Robert Orban, Chief Engineer, Orban, Inc., A Harman International Company, rorban@earthlink.net

Audiophiles need scientists
Editor: David Del Bourgo's "somewhat educated guess" ("Letters," September '99, p.13) in fact betrays his ignorance. He merely repeats one of the most frequent libels against scientists and engineers: that we reject or even avoid all subjective experiences and are devoid of all "right-brain" activity! The truth is that if you visit any science or engineering establishment, you will find a much higher level of participation in the arts among its workers than in any other professional group. More important, you will also find an equally high level of ownership of high-end audio equipment in their homes!

The irony is that audiophiles rely absolutely on the very people they despise to develop the ever-better equipment that they demand. To design something "better" requires that the magnitude of one or more measurable parameters be specified as in need of increasing or decreasing. Without such terms of reference, it would be impossible to start the job. Since the overall aim is to accurately record and reproduce audio sound as far as a human observer is concerned, the subjective experience of any improvement is always tested. This is always done using the body of (scientific) knowledge of human physiology and psychology, as well as acoustics. Hence the use of specially designed listening rooms and double-blind testing. It is also accepted that individual human senses can be trained to higher levels of sensitivity than the general population, and that such "expert listeners" will be used where very fine differentiation is sought.

Mr. Del Bourgo's sneering tone as to the philistine nature of the scientific community is a common cover for anti-scientific views. I am certain that it is not the scientists who have to strive to understand human subjectivity, but rather those who proudly parade their scientific ignorance who should strive to understand science.—Malcolm Herring, Menlo Park, CA, malcolm.herring@btinternet.com

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