Tape Guide (Aug. 1978)

Line Length

Q. I would be interested in information concerning the maximum length of microphone cable I can safely use with my tape deck.

-Herman DeVries; Union, Iowa.

A. if you are using high impedance microphones--over 10 kilohms output impedance-don't use more than about 15 ft. or 20 ft. at the very most.

However, a low impedance mike of about 1 kilohm or less allows you to use upwards of 100 ft. of cable.

Deck Decision

Q. I've been having a problem trying to choose between two tape decks.

One is rated at a ±3 dB frequency response, while the other is at ± 2 dB. Is there a substantial difference between them?

-Allan Mandeville; APO N.Y.

A. A tape deck with a flat frequency response within 2 dB will give slightly better audible performance than one flat within 3 dB, assuming both cover the same range, say 30 Hz to 15 kHz and both conform to specifications.

Keep in mind that the deck rated flat within 2 dB has a total swing of 4 dB, while the other has a swing of 6 dB.

Mono Mishap

Q. I have a Sony tape deck with which I'm not too familiar. I recently received some four-track mono tapes and I find that when I play these, two tracks play through two speakers at the same time, therefore, I must turn off one of the speakers in order to hear the other clearly. Is it at all possible to have one track playing through both speakers?

-George Marashian; Milford, Mass.

A. Whether or not you can play four mono tracks one at a time depends upon the switching facilities of your particular tape deck or audio amplifier. Some decks allow you to play one track at a time, while others force you to play two at a time (stereo mode). However, many audio amplifiers allow you to feed one incoming signal (left or right) into both channels. Therefore, I suggest that you consult the tape deck and audio amplifier instruction manuals to see if one or the other permits you to switch one signal into both channels. If the manuals aren't clear on this point, consult your audio dealer or equipment manufacturer.

Dolby Economics

Q. I am confused over the various Dolby noise reduction units on the market, with prices varying over a wide range. Are the cheaper units only for playback of Dolby recordings?

-D.D. Woodruff, San Rafael, Calif.

The less expensive Dolby units employ the same electronics for recording and playback; this means that you cannot simultaneously record and monitor a tape with the Dolby frequency characteristics. Instead, you must first record the tape with the Dolby unit, then play it back with the Dolby unit at a later time. The more expensive units enable you to simultaneously record and play a tape with the Dolby characteristics. Also, the more expensive units may incorporate additional features such as microphone mixing, VU metering, etc.

Quality Quandry

Q. Does erasing and recording over previously recorded material affect the quality of the recording?

-David Hunt, Rockland, Mass.

A. Tape that is completely erased is suitable for repeated use in recording.

If the tape machine's erase head cannot achieve complete erasure, use a bulk eraser. Otherwise, though this takes much longer, put the tape through the recording process with no signal input to "pre-erase" the tape.

Then the tape is erased a second time when you use it for recording.

If you have a problem or question on tape recording, write to Mr. Herman Burstein at AUDIO, 401 North Broad Street, Philadelphia, Pa. 19108. All letters are answered.

Please enclose a stamped, sell-addressed envelope.

(Source: Audio magazine, Aug. 1978; by Herman Burstein)

= = = =