THE CASSETTE: A SHORT HISTORY
THE Compact Cassette was introduced in 1964 when STEREO REVIEW was a precocious six-year-old. Presciently enough, a few prognosticators even then foresaw a brilliant future for the (then) curious little format and they made so bold as to predict as much publicly. This was very close to a reckless prophecy, for of all the record/playback media available at the time, the cassette was surely the least promising. With its unprecedentedly narrow tape tracks and 1 7/8-ips speed, the cassette had no high-frequency response to speak of, no speed stability, and plenty of tape noise. Many mistook it for a clever and convenient speech-dictation medium with amusing ambitions. But even then the inventors of the cassette knew better, and history has proved them right.
Credit for devising the cassette in the first place goes to Philips of the Netherlands and Staar of Belgium. When component cassette decks first began to reach the market there was a brief flurry of debate over the "Staar System," a transport mechanism in which the cassette was inserted edgewise into a loading slot-as opposed to today's more familiar cassette "well," which provides for angled insertion of the cassette into a suitably shaped receptacle. Otherwise, there was little technical controversy worth mentioning in the early years of the cassette's existence.
Under the Norelco name Philips exported a few cassette changers to the U.S. market, where they languished for lack of general appeal and credibility (although from all reports they worked quite well). A previously un known Japanese company called TDK began offering an "SD" tape formulation that claimed to (and did) give a somewhat more prominent and extended high-frequency response and a gratifying freedom from "drop outs" caused by imperfections in the oxide coating. The cassette was meanwhile gaining great strength overseas as a music medium for automobiles, while the eight-track cartridge held sway in the U.S. And as for prerecorded music cassettes, their sound quality was vigorously deplored from coast to coast in this country.
The times demanded change, and the change came very quickly. Some years previously, Henry Kloss (the "K" in KLH) had prevailed upon Dolby Laboratories to create a scaled-down (from their professional system) "compander" noise-reduction system that would suit the requirements of home recordists in the elimination of tape noise. The resulting Dolby B-type noise-reduction processor found its way into a KLH open-reel ma chine that, when everything was going right, could genuinely challenge the performance of much more elaborate tape recorders operating at higher tape speeds. The KLH deck foundered commercially, but when Kloss founded his own company, Advent, the Dolby-B processor was still on his mind, and he felt that the cassette format was where it would find its happiest application. The Advent 200 deck that resulted from this conviction brought the cassette into the realm of high fidelity. With a frequency response approaching 14,000 Hz (as opposed to the 9,000 or 10,000 Hz that was the usual figure at the time) and an effective signal-to-noise ratio exceeding 50 dB, the Model 200 could deal competently with any off-the-air taping chore and do justice to many LP discs as well.
----- The original Norelco Carry-Corder
Meantime, a fight for dominance was shaping up between the cassette and the eight-track cartridge. The cassette had smaller size, familiar (more open-reel-like, that is) handling characteristics, a rudimentary if problematic editing capability, a slight edge in the in-home market, and the Dolby system. The eight-track cartridge had a higher tape speed, a wider track, a considerable lead in the automotive market, and easy four-channel sound capability. The originators of the cassette concept (most notably Philips) held back from adopting a special standard for, quadraphonic sound. In retrospect it appears they may have been wise, but the eight-track format em braced four-channel sound immediately, and this made a definite difference in the cartridge's appeal in automotive and other low-to medium-fi applications.
The battle for technical supremacy was decided through eight-track's failure to innovate. Eight-track cartridge decks incorporating the Dolby system were very few. Further more, DuPont had come up with a metallic oxide-chromium dioxide ( CrO2)-that had a capability for slow-speed, high-frequency recording vastly superior to anything then available. Advent championed this new tape formulation, and in a joint effort with Dolby Labs and DuPont managed to establish a new equalization standard for CrO2 that raised the high-frequency and signal-to-noise performance of the cassette far above anything eight-track could approach in its standard form. The CrO2 tape required a higher bias signal than conventional cassettes, and a different equalization characteristic as well.
At just about this time, as it became plain that the cassette, despite Philips' conservative approach, was becoming an "anything goes" format, a number of its fans began to visualize the ultimate cassette deck. It would have three heads instead of two in order to permit off-the-tape monitoring and to facilitate correct design of each head for its particular function. The critical playback head would of course have to be positioned opposite the cassette's built-in pressure pad, thus ensuring good tape-to-head contact. The record head would therefore be deprived of a pressure pad, but an adequate substitute should be possible in the form of a dual-capstan drive that would create a certain amount of tension in the tape as it passed over the heads, literally pulling the tape into close con tact with the record-head gap. I recall a certain amount of ungracious snickering when these ideas were first proposed, but it was to be only a matter of months before a machine embodying them was standing before us, first titled the Concord-Nakamichi Model Z and then the Nakamichi Model 1000.
SINCE that glorious introduction, three-head cassette decks have become almost common place. Hitachi soon devised a head configuration in which the record and playback heads nestled snugly in one head housing so that their various gaps could share a cassette's pressure pad. The impact of this innovation was primarily economic, in that it made the three-head configuration affordable if not truly inexpensive. Now we face the prospect of new tapes, such as 3M's "Metafine," that promise to extend the cassette's high-frequency response out to virtual infinity and render its present overload problems a dim and distant memory. As a product that has far exceeded its inventors' most optimistic expectations, there has perhaps been nothing like the cassette since Thomas Edison's little tin-foil "dictation" recorder. Quite possibly, there will never be anything like either of them again. But let's not close the patent office just yet anyway.
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by: RALPH HODGES
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Source: Stereo Review (USA magazine)