News and Views: Time-lapse audio ... Lincoln Center on TV... Cassettes of the future.
Cooking on the Back Channels
Not long ago we were approached by a gentleman from Audio Pulse, which has a prototype of an audio delay unit.
Would we like to hear it? Well, we're always ready to lend an ear or two to a new audio idea.
Audio Pulse is a newly formed division of Hybrid Systems, a Boston-area manufacturer that has up until now specialized in computer technology. In concept, an audio delay unit is a simple device. A signal is fed into its input and emerges from its output after a predetermined time (perhaps several milliseconds) but is otherwise un changed. Other devices have been available for this use--echo chambers, tape loops, spring reverberators, and the like-but all suffered from marginal performance or exorbitant price or both. Their purpose is, of course, to add synthetic reverberation to existing recordings--or live sounds, for that matter.
We had been aware that computer technology had been applied to this problem, but we also knew that the equipment available carried very high prices. The Audio Pulse mechanism is the first that we've seen designed for the consumer market. (The company expects to sell a stereo unit for about $500.) The device takes a music waveform and changes it into a string of digits that chase each other through a series of storage cells and are converted back to a music waveform at the other end. This in itself would pro duce only a single delay, insufficient for convincing simulation of reverberation, so several different delays are used.
In addition, signals are fed through the unit several times and are even bounced back and forth between its two channels.
The over-all effect is astonishingly realistic. With the simulated reverb fed through the back channels of our four channel setup (our guests denied all connection with conventional quad, even in the placement of the speakers), we could, by twisting a few knobs, turn our rather "dead" listening room into a small auditorium, a large concert hall, a cathedral, or even a cave (a somewhat bizarre effect). Moreover, the reverberance came from in back of (and seemingly all around) us, rather than just from in front, putting us effectively in the middle of the acoustic "space"-which, of course, can't be accomplished with conventional stereo. An additional feature allows some re verb to be fed into the front channels, which heightens the effect even more.
Subsequent developments suggest that this idea may be catching on; a second Boston-area company reportedly plans to introduce a similar unit, and as redoubtable a manufacturer as Phase Linear also has something in the works. Audio Pulse hopes to be in manufacture sometime this month.
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And the Music Is So Restful, Too
Here it is, folks: a solid walnut enclosure for your whole stereo system. Well, maybe its not quite what you had in mind. But James L. Anderson, a mortician who lives in Metairie, Louisiana, finds that it works quite well. He assures us that, contrary to appearances, the system-which includes a PIC VR-5535X receiver, an Akai CS-500 cassette deck, a Roberts four-track stereo-video recorder, and a Garrard turntable, in addition to the Creative Model 88 speakers seen (grieving?) at the sides-is alive and well.
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Cassettes of the Future? (Part I)
There are relatively few cassette tapes, out of scores on the market, to which recorders actually are adjusted in manufacture. Manufacturers can often seem downright obscurantist on this point. Yet, if you use a tape with a recorder adjusted for a significantly different type, the unavoidable result is a high-low imbalance in the sound.
TDK SD was the choice of recorder manufacturers a few years ago. Then Maxell came along with UD, and producers of decks found that it would deliver a little better performance than SD if the decks were readjusted for UD- meaning slightly higher bias. So UD became the tape, and some tape manufacturers actually came out with very close matches: Fuji's FX, TDK's Audua, Nakamichi's EX, even Maxell's own UD-XL are examples. They're not identical, of course, but they are (mercifully) interchangeable without mismatch to the recorder.
It would be helpful, then, if there could be a standardized terminology about tape types. Say we called the bottom rung Group I, for a good tape of modest price-some thing like BASF SK might serve as the model. Group II could be SD and compatible tapes. Group III could be UD and its match-mates. Perhaps Group IV could be chrome and TDK's SA (which in terms of bias and equalization, if not output, is interchangeable with chrome). Then both cassettes and deck switch positions could be unequivocally labeled for compatibility; the manufacturers of each would know what to expect of the other's products; the purchaser would be freed from guesswork. Glorioski! We were ruminating on this subject recently with Ted Nakamichi of Nakamichi Research, and he seemed some what taken aback. His company, it seems, has been considering an approach along these lines. Three cheers for Nakamichi! Perhaps others are, at this very moment, thinking along similar lines. But it will take much more than a few manufacturers to make such a system work.
The industry would have to agree on bias currents, recording equalization curves, and Dolby-level adjustments. But if it did, you could buy a Group II tape and know that it would deliver flat response with any deck bearing the Group II label or with a Group II switch position. You would know, if you bought a Group III deck, that any Group Ill tape would be good but that, if you saved a little money by buying Group II, you'd have to give up some high-end response-and even more with a Group I tape.
From March 1 to 3 the International Tape Association, representing both hardware and software manufacturers, will be meeting in Tucson. Is it too much to hope that some member of the industry will bring the subject up for discussion?
Cassettes of the Future? (Part II)
And while we're on the subject of tape types, we might mention that there seem to be growing rumblings within the industry about chrome. Two deck manufacturers have told us they expect chrome (and ferrichrome) to disappear from the market within a few years. They give several reasons: By comparison to a good ferric, chrome's distortion is higher; it wears tape heads a little faster; it is more brittle and therefore harder to coat permanently onto ultra-thin backings; the raw particle is relatively unreliable (one manufacturer says as much as 60% is rejected for tape manufacture as out of spec); and-far from keeping up with the rapid development of ferric particles-it presents little hope of significant improvement. At this writing at least one deck manufacturer is thinking of adjusting its high bias position for TDK SA instead of chrome; at least one tape manufacturer plans to recall all its chrome product.
But, again, one manufacturer in each field does not a landslide make.
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(High Fidelity, Mar. 1976)
Also see:
Too Hot to Handle (Jan. 1977)