TAPE GUIDE (Apr. 1991)

Monitoring Noise

Q. I am concerned about a high frequency noise, sometimes referred to as head coupling, which I hear when monitoring from the tape during recording. Is there any way that I can get rid of this noise so that I can calibrate my deck better by monitoring when recording? Are other three-head cassette decks victims of this problem?

-Bill Kafato; Winnipeg, Man., Canada

A. In a three-head cassette deck, the record and play heads are necessarily very close together. When Philips designed the cassette format, only a two-head arrangement was originally visualized, although clever engineering subsequently made it possible to squeeze in a third head. It appears, in the case of your deck, that there is an interaction between the two heads which results in the high-frequency noise you hear when monitoring as you record; possibly this could be due to oscillation owing to close coupling. I haven't run into this phenomenon before. It may be an artifact of your particular deck, and the problem should be referred to the manufacturer or to an authorized service shop.

Azimuth Problem

Q. About 2 1/2 years ago I purchased a high-quality cassette deck that had been used as a demo unit. After a year, during which I recorded about 80 tapes, I bought a car deck. None of my tapes sounded as good on the car deck as on the home one; the music became muffled; a thick cloud seemed to mask it. Every deck on which I played my tapes produced the same effect, so the fault proved to be with my home deck: Its record-playback head is out of correct azimuth alignment.

The manufacturer states that for $50 it will fix the problem, clean the deck, and make sure that everything is up to specs. But if the head azimuth is changed, all my tapes will sound (expletive omitted). I know there is a solution--buy another deck, new this time, and use it to dub tapes played on my present deck. However, this solution is not financially possible for me now. Can you suggest something?

-Stuart Zimmerman; Solana Beach, Cal.

A. First of all, $50 (excluding parts) is a very reasonable charge today for putting a deck in proper operating condition. A possible solution to your problem is to borrow or rent a high quality deck for rerecording your valued tapes. Play them on your misaligned home deck and record them with the borrowed deck. Then send your deck in for servicing.

Sensitive Questions

Q. The other day I was recording a metal-particle tape at a level of +7 dB. When I played it back, the meters peaked at only +3 dB. Why is the playback level lower?

I have a prerecorded tape that was recorded at +4 dB on Type I tape. But when I try to record on Type I tape at +3 dB, it distorts. Why is this?

-Brian Gebhardt; Carlstadt. N.J.

A. In answer to your first question, one reason is the sensitivity of the tape you used. Sensitivity denotes the level of tape output for a given level of input.

Tapes of various brands and levels of quality vary in this respect, and you may have been using a tape of relatively low sensitivity. (However, low sensitivity does not imply low quality in other performance respects.) The reason may also lie in the calibration of your tape deck; that is, the meters may not have been calibrated properly at the factory to make playback level correspond with recording level for most tapes. But this is not a serious fault and should not concern you. If, in the future, your deck has to be serviced for serious reasons, you can have the playback calibration adjusted.

One reason why a prerecorded tape can achieve a high playback level is the use of a tape with high sensitivity, so that for a given recording level-corresponding to maximum acceptable distortion--a relatively high playback level is obtained. Or, for a given distortion level, the chosen tape may be able to accept a relatively high recording level. Also, the use of the Dolby HX Pro headroom-extension system by the tape duplicator permits a higher recording level in the treble range before tape saturation takes it toll in distortion and treble loss.

(Source: Audio magazine, Apr. 1991, HERMAN BURSTEIN)

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