By CRAIG STARK
THE BEST TAPE CASSETTE?
I'm often asked by friends (and by friendly readers), "What is the very best cassette I can buy for use in my deck?" Since I write a lot about tape, it's a natural question, and since I've recently conducted test measurements on samples of some thirty different brands, you'd think I could give a straightforward answer. But I can't, and the reasons have nothing to do with offending some important manufacturer whose tape didn't test as well as he thinks it should. Nor is it a quality-control problem that makes generalization difficult.
The real "losers"--the unbranded "specials" you get for 59R each at discount outlets--are easy to spot by any kind of measurements or critical listening. But among the "winners" it's hard to give a strict priority ranking, for two different reasons. The first is that cassettes, even more than open-reel tapes, constitute a kind of "unified system" with the recorder on which they are being used. The overall performance of the cassette depends on two very distinct internal factors: the tape itself and the plastic-shell housing including the guides within it. The second reason is that the cassette machine's internal adjustments (bias and equalization) count so heavily.
Taking the "top" seven cassettes I could find, the "rank ordering" on one consumer cassette deck (of the four I used) on a completely uncontroversial record-playback measurement (output level for a constant mid-frequency input), I ranked them 1 through 7. Using the exact same sections of tape on a different cassette machine, the ordering went: 1 5-4-2-3-7-6. Obviously, the moral to be drawn is that if the manufacturer of your deck specifies that a particular type or brand of tape was used for setting up the recorder, start with that before you experiment with others.
Whether the two parts are secured by screws or by sonic welding, the top and bottom halves of the cassette must "mate" perfectly. The "guide pins" or rollers must be accurately set inside the shell, and the pressure pad must be exactly positioned and set for proper tension or your high frequencies are going to suffer. Using a lab recorder, I've measured high-end differences (above 10 kHz) of 10 dB between samples of the same cassette (not a well-known brand) that are possibly attributable to these causes alone. And, of course, if a manufacturer does not keep the most scrupulous control over the oxide, resins, sol vents, film base, coating thickness, and so on of the tape he puts into those shells, testing results can be expected to diverge wildly.
This brings up the second, more philosophical reason I can't tell you which cassette is "best." Do those of us who test tapes, and especially cassettes, in which the problems are magnified by slow speed and narrow track-width, really know what parameters to test? I'm increasingly dubious about this. We in the testing fraternity may be missing-or misinterpreting- something our graphs and meters display. Those who judge quality primarily by meter readings would have no hesitancy in saying that 50 percent intermodulation distortion has to sound worse than 1 I percent results I actually obtained. However, listening to music recorded on the tapes that produced those readings with test tones certainly did not confirm that dramatic difference. As a matter of fact, the rising frequency response of the first tape (which was largely responsible for the 50 percent IM reading) may be just what your machine needs to give more realistic reproduction. The moral here is that you must try a variety of different cassettes on your machine-not with test tones, but with music-in order to judge which is the very best in respect to the "electrical" qualities such as noise, signal-level overload, etc. However, mechanical problems within the cassette, or momentary loss of signal level (dropouts) are faults that are readily testable and demonstrable to the ear or a test instrument.
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