TAPE GUIDE (Jun. 1988)

Proper Calibration

Q. I understand that matching of record and playback levels in taping a cassette is important for proper tracking by a deck's Dolby circuits. If I correctly match levels, using the adjustments provided in my deck for this purpose, will the tape that I have re corded on my deck be tracked properly when played back on another deck?

-Timothy Donovan; Lexington Park, Md.

A. If, for a given tape, two decks are properly calibrated with respect to Dolby level-based on a Dolby-level test tape employed by the manufacturer or a technician--a Dolby-encoded tape made on one deck will play correctly on the other. If there is mis-calibration, treble response will tend to be affected adversely, usually in the form of treble loss. Fortunately, there is about ±2 dB of latitude in matching levels before adverse effects become serious.

Complaint Department

Q. I would like to know if you share my viewpoint concerning the quality of today's cassette decks. It seems we have gone backwards. Mid-priced decks have more wow and flutter, and weigh less, than those of five years ago. They have a cheap feel, and I find a lot of them actually sound worse than the earlier ones. It bothers me that companies are all too willing to focus attention on features which do nothing to improve the sound or increase reliability; in fact, they often detract from performance. Manufacturers always look for ways to keep costs down, but unfortunately it's the bells and whistles that catch consumers' eyes. Why do major companies focus their attention on auto reverse and double wells? Why do they offer $200 or $300 decks which have auto reverse,' programmability, electronic tape counters, microprocessor this and microprocessor that, but which also have high wow and flutter, terrible frequency response, muddy bass, Permalloy heads reminiscent of those used a decade ago, poor transports, etc.?

- Steve Medel; New York, N.Y.

A. I have to agree somewhat with your observations; while there are companies making very good cassette decks, others are not. At times it seems there is almost an inverse relationship between price and number of features. It appears that in some companies the factory makes what the marketing department believes it can sell, rather than the other way around.

In this and other ways, it seems that we are in the age of hype fidelity.

Thin May Be In

Q. Your September 1987 column recommended against using tapes thinner than 1 mil for open-reel decks. I once owned a Tandberg open-reel deck; Tandberg's great claim to fame at the time was that their decks made good recordings at slow speeds. At 3 3/4 ips, my deck made tapes that were flat to well beyond 18 kHz with just about any brand of tape, provided the bias was adjusted properly. For me, the biggest problem was not hiss or distortion, but dropouts. I noticed that thinner tapes had considerably less of a dropout problem than thicker ones.

Tandberg was aware of this and recommended tapes that were 1 mil and thinner. It appears that the greater flexibility of thin tapes allows more intimate tape-to-head contact. If I wanted to use the 1 7/8 ips speed of my deck, 0.5- or 0.75-mil tapes were the only ones I could use satisfactorily.

I agree that using thin tapes on professional machines is asking for trouble. But on home-type transports de signed for 7-inch reels, thin tapes will not stretch if reasonable care is used.

True, there is a bit more low-frequency distortion and reduced S/N, but as for print-through, at the slower speeds the primary printing frequencies are moved into the upper bass and there fore are not that much of a problem. As far as I'm concerned, 0.5-mil tapes are quite suitable for high-fidelity recordings, so long as reasonable care is taken and limitations are under stood.

-Steve Graham; Ann Arbor, Mich.

A. My own experience with thin tapes (less than 1 mil) for open-reel machines has been negative. Also, the NAB Standards, at least in the past, have stated that thin tapes are not recommended. However, all this is well in the past, and doubtless thin tapes have improved over the course of t me, along with all other tapes. This even applies to very thin cassette tapes, the C-120s. Not long ago, several readers pointed out to me that some makes of C-120 tapes provided satisfactory results; until then I had been very negative about them.

While I am not prepared to heartily recommend extra-thin tapes to home recordists, I shall keep in mind that some people, like yourself, have found them satisfactory and even advantageous, and that they are worth trying.

Unkeyed Cassettes

Q. I have come across several pre recorded CrO2 cassettes that will not register as such in my deck. Although the cassette labels say CrO2, Type II, the shell does not have the required depressions to activate my deck's automatic sensing system. Don't the tape manufacturers know that many modern decks incorporate sensors which switch the deck automatically to proper bias and equalization according to tape type? If they do know, why don't they at least leave tabs that con sumers can punch out?

-Timothy Eckert, Madison, Wisc.

A. There are two possible reasons for the absence of this notch. The first possibility is carelessness or indifference on the part of the suppliers of the prerecorded tapes in question. This includes the chance that proper keying was accidentally omitted. The second possibility is that the omission of CrO2 identification notches from these tapes is not a mistake at all. Many prerecorded cassettes are recorded with Type I (120-uS) equalization even when they are made on Type II tape. This is done to ensure compatibility and proper Dolby NR tracking on those decks which do not have equalization selector switches of any kind. By omitting the notches, the tape duplicators are probably preventing your deck from automatically selecting the wrong equalization, rather than preventing it from using the right one.

Some of the blame for problems of this nature also attaches to those deck manufacturers who fail to provide for manual as well as automatic selection of bias and equalization in accordance with tape type. In a world where Murphy's Law operates, I don't think that deck manufacturers should assume that cassette shells will always be properly keyed.

Excessive DynamicRange

Q. I have a dynamic range problem: There's too much of it in the tapes that I make. They are beautiful tapes, but in my car the road noise and engine noise mask all but fairly robust sounds.

The result is that I must either give up the softer parts of the music or put up with excessive climaxes. I have achieved some success with dbx NR encoding and playing back without de coding, but the frequency response then sounds thin. Any ideas?

-Norm Strong, Seattle, Wash.

A. Check the section on Signal Processors in Audio's latest Equipment Di rectory (October 1987), and you might find a compander within your price range. Such a unit would permit sever al user-selectable degrees of compression rather than the fixed and severe amount provided by a dbx noise-reduction unit.

Alternatively, you might continue to use your dbx encoder (compressor), but with equalization in recording to produce a final result that is more or less satisfactory for car use. Equalizers are available today at fairly modest prices.

A third course would be to ride gain when recording. This assumes you have very good prior familiarity with the material so that you can accurately anticipate loud passages and reduce re cording level temporarily.

With only one or two exceptions, manufacturers of CD players and cassette decks have failed to give attention to the problem of excessive dynamic range-understandably, because great dynamic range is one of the boasts of the CD medium. This problem can exist in the home as well as in the car. I have at least one CD which requires a volume change in mid-course if I am to avoid distressingly loud sound yet hear the softest pas sages. To some extent, the makers of CD equipment are only doing what they should, in capturing the widest possible dynamic range. But this can easily cause a dubbing problem.

(Source: Audio magazine, Jun. 1988, HERMAN BURSTEIN)

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