The Music Lab Auditioning Facility (MLAF) at California Institute of Technology is available under contract for listening tests of audio component. Consultation is also available for those wishing to set up their own facilities for listening tests.
The MLAF consists of the Music Lab and its recording, playback and measurement equipment; Dabney Lounge (with Steinway concert grand rebuilt Sept., 2000, by Jim Bryans); and permanent cables between the two.
Music class in Dabney Lounge.
MLAF will carry out listening tests of prototype or existing components using either stored material or a direct microphone feed. Direct-feed tests are almost unknown in the audio industry; but I feel they are essential because no bench tests are known to correlate generally with human perception. It's been known for decades, for instance, that "total harmonic distortion" (THD) does not correlate with perceived quality. (See RCA Radiotron Designer's Handbook, ed. F. Langford Smith, 4th Edition, 1953; also various Research Dept. reports of the British Broadcasting Corporation). Yet the industry blithely continues to quote THD as though it meant something. Ironically, where a THD spec is required by law, in power amplifier ratings (Federal Trade Commission regulation, part 432 of 16 CFR Ch. 1, 1-1-96), almost no companies comply.
Listening tests using microphone source are far more demanding than those using stored material. Such tests allow one to form judgments more quickly, confidently and accurately than tests from stored material.
Of course high-quality stored material is also useful, especially for preliminary auditioning; and is available in the MLAF off CD, Lp, DAT and soon from high-bit digital source. The Lab also owns highly-praised commercial releases in which I've participated as as performer, engineer and/or producer; so I know the original sound very well.
Listening evaluations may be done on-site by clients or by me on their behalf. (I have over twenty years' experience as an audio consultant.)
Philosophical digression: Perhaps meaningful specs are not known for the fundamental reason that we're still too ignorant about how our ears and brains process sound. The late Michael Gerzon, of the Oxford Mathematical Institute, co-inventor of Ambisonics and the Soundfield Microphone, and a world expert in spatial aspects of sound, said that if you gave him the signals from a person's two ears, told him that the sound was created by a flute, and asked how far was the flute from the person, he wouldn't have the first idea of how to figure out the distance. Yet humans perform the task effortlessly and unconsciously.
Not only are meaningful bench tests virtually nonexistent, but designers' intuition also is largely missing: Pick a component widely accepted as sonically outstanding, and still the chances are good that other components by the same designer will be merely ordinary in sound quality.
This isn't to say that the right things can't be measured, only that right now, no one yet knows what to measure. Thus, the only way to assure the sonic quality of a new design, or an alteration to an old design, is to listen.
Music Lab measurements may be carried out using Hewlett-Packard spectrum analyzers models 3582A (25 kHz) and 3567A (102.4kHz), microphones of 20- and 100-kHz bandwidths by Aco and B&K, ultra-low-distortion Krohn-Hite oscillator, MLSSA, LEAP, etc. Some of this equipment was used for a paper on the wide-band spectra of musical instruments.
Rates will be quoted on a per-hour basis and an advance will be required; and will vary depending on how much of the MLAF facility and of my time (under separate contract) are required; and on whether an oral or written final report is requested. The optimal way to use the Music Lab is to involve it interactively in an ongoing design process, rather than for a ‘one-shot' test.
Serious inquiries only, please.
Pasadena, CA 91125
Tel +626 395-4590