Author: F. Alton Everest.
Course Materials: Five cassettes or open-reel tapes and 108-page manual.
Price: With cassettes, $129.95; with open-reel tapes, $199.95.
Company Address: 31121 Via Colinas, West Lake Village, Cal. 91362.
Critical Listening is a training course aimed at those considering music-studio careers, but its potential usefulness to audiophiles is obvious. The version I reviewed consists of a 108-page manual and five cassettes, with one "chapter" or lesson on each cassette side.
The course's level is quite basic, and the treatment appropriately diagnostic, concentrating not on "good" or "bad" sound but on the ability to analyze what one actually hears. As the manual puts it, the course is "based upon the premise that . . . discriminating listening ability, which appears so remark able and complex when viewed casually, can be subdivided into a number of simpler parts which are teachable." I listened to the cassettes with a female colleague whose hearing is probably better than mine but perhaps not so critical. We heard the same things in all cases. She was surprised at the emphasis on values she considered musical rather than technical, but for someone who will have to equalize tapes to the satisfaction of musicians, the emphasis is right.
Cassette side one ("Estimating the Frequency of Sound") deals with the audio spectrum, and teaches the association of pitch with actual frequency for single tones and narrow-band noise signals. The object is not to determine whether you can hear 22,000 Hz, but to see if you can confidently select the right equalizer band to make a desired change. Side two ("Estimation of Sound Level Changes") does the same thing for perceived loudness versus actual sound levels, with the manual providing very basic notes on the logarithmic derivation of the decibel.
Side three ("Estimating Frequency Band Limitations") presents deliberately band-limited program material and general instruction on detecting frequency-response limitations. All these sides, and the ones that follow, conclude with little quizzes.
Side four ("Frequency Response Irregularities") progresses into multiple peaks and dips in frequency response, finishing with some valuable tutorial on the behavior of lavalier microphones.
Side five ("Judgment of Sound Quality") discusses the audible differences between simple and complex wave forms, the contribution of the fundamental frequency to the perceived sound, and the effect of depriving musical instruments of their overtone structures. Side six ("Detecting Distortion") treats harmonic distortion, wow, and flutter.
Side seven ("Reverberation Effects") takes on the meaty subject of reverberation time and its influence on music and speech intelligibility. The reverberation is artificially generated, but the conclusions arrived at are generally valid. Side eight ("Signal versus Noise") defines signal-to-noise ratio and acceptable noise levels, and demonstrates some often-encountered noises of electrical and mechanical origin. Alas, some of the noises, such as a touch of hum here and there, have been introduced unintentionally.
Side nine ("Voice Colorations") delves pretty deeply into good micro phone practice, and contains excellent information that many working professionals seem to ignore. The recorded examples are of speech only, but the problems translate directly to music re cording. Use of acoustical absorbers to eliminate local sound reflections to the microphone is not touched on at all, but at least the student gets a clear idea of what havoc such reflections can raise, and is taught some of the reasons why multi-miking has been falling out of fashion.
Side 10 ("Listening with Discernment"), described as a review, is an exam that asks the listener to identify flaws which have been deliberately introduced into 10 musical excerpts.
Critique
The principal problem I find with Critical Listening is that while it is a splendid guide to making or understanding a good recording, it is not itself a good recording. Chromium-dioxide tape is used, but without noise reduction. As it happens, noise--except for modulation noise--never becomes a significant fault, but this is probably because compression and riskily high levels are employed throughout. There is print through (most blatant on the frequency sweep of side one) and a fair amount of high-frequency overload and other distortions. There is also a distressing tendency for some of the purposefully flawed examples to sound 'better, or at least more accurate, than the properly executed reference (as when the cardioid microphone, placed at the "correct" distance from the narrator, comes through with far mere proximity effect than I like to hear). This mystery sent me and my cassette deck to the test bench several times, to make sure that all was well with the machinery. It seemed to be.
The most annoying part was the brief snatch of TV-commercial music that is used throughout the course to demonstrate good and impaired sound. Evidently it is a stock item from a tape library (rights to original material for projects like this are hard to come by), and whatever it sounded like when it was rented, it comes to us on these cassettes with something like 10% distortion in its "clean" version. This doesn't mean you can't hear the deliberate distortion increases of side six: the added increments of THD are substantial. But it does mean that a reference to good sound is lacking, and this can become a distraction when you're listening for flaws other than distortion in other sections of the course.
(Incidentally, Mr. Everest, the author, tells me that distortion levels for side six were established by raising the re cording level until a steady tone achieved the desired amount of distortion, and then recording the music with the VU meters peaking at that level.) Aside from a few other quibbles (for example, the violin and piano of side five are not precisely in tune), I'm inclined to award Critical Listening full points for value and validity of concept.
I can see this course, or something like it, doing good service for a technical library or an audio club, its somewhat high cost notwithstanding. Does it adequately define what critical listening is really all about? It certainly puts its finger on many things that make listening unpleasant, and by implication suggests what can be done to improve matters. Also, I would have to say that if you can't hear the points that this course is trying to make, any hopes you might have of becoming a critical listener are fanciful indeed.
-Ralph W. Hodges
(Source: Audio magazine, Jul. 1983)
Also see:
Influence of Listening Rooms On Loudspeaker Systems by Roy F. Allison (Aug. 1979)
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