Tape Guide (Jul. 1980)

Equalizing Recordings

Q. I am interested in an equalizer to clean up some muffled and boomy tape recordings. What features should I look for?

- Wendy Rickert, Boulder Creek, Calif.

A. Generally speaking, you should look for at least five bands of equalization in each channel (10 bands are preferable), very low distortion, absence of ringing effects, wide and flat frequency response when filter action is inactivated, high signal-to-noise ratio, and at least 12 dB of boost and cut in each band. The ability to change the filter "Q" or relative width of the filter is also of value, as you may wish to equalize only a narrow portion of the frequency spectrum; this is available in a parametric equalizer.

High-Level Noise

Q. After more than a year of consideration, comparison, conversation, reading, and budgeting, I decided that a particular model was far and away the best open-reel tape deck available for the money. I took the plunge. I like the unit. It's everything it's claimed to be--except for the very noticeable noise in the playback amplifier at relatively high levels after recording in the normal manner. My dealer recommended that I tape at a high level using a good-quality tape. After some experimentation I can record just below tape saturation and get away from the noise. But taping at such a high level seems to change the overall response of the machine--highs are attenuated and lows are accentuated. What would you recommend? Live with my present situation? Change internal alignment for correct response? Or what?

-Skip Laughlin, Tulsa, Okla.

A. I suggest that you take your tape deck, together with the tape you plan to use, to a competent technician and have him optimize the machine's performance in terms of adjusting bias, record equalization, audio drive cur rent, and record level indication in accordance with the instructions of the tape deck's manufacturer. Even if it turns out that no changes have to be made in these adjustments, the expense is still apt to be worthwhile for the peace of mind in will give you.

Any tape machine will produce noticeable noise in playback at very loud levels. The S/N ratio of the best tape decks isn't up to that of the best amplifiers, although this differential is steadily diminishing. When you record at a level close to tape saturation for the body of the signal, chances are that you are getting into saturation at the high frequencies. Saturation of the high frequencies, therefore, accounts for your impression of attenuated highs. And attenuated highs, in relative terms, give an impression of emphasized bass.

Flip-Side Crosstalk

Q. I have an open-reel tape deck which is truly wonderful in all respects but one. The problem is what I feel to be an unacceptable level of crosstalk from the flip-side program material.

Especially prominent are bass and percussion instruments, and the problem is particularly annoying during quiet portions of the side that I am listening to. Is there some defect in the deck? Since the deck is still under warranty, should I have it checked out by an authorized repair shop?

-James Engel, Uniondale, N.Y.

A. Your crosstalk problem is definitely not normal and should not occur to an audible extent in open-reel decks with any pretension to quality. The problem appears to lie in vertical mis-positioning of the record head with respect to the playback head so that tracks recorded on side B (flip side) are partially scanned by the gaps of the playback head. From top to bottom of the tape, which is assumed to be running from left to right, the tracks are numbered 1, 2, 3, 4, with three "is lands" separating them. Tracks 1 and 3 are for recording in direction A; tracks 2 and 4 are for direction B (flip side). If the record head, say, is vertically mis-positioned, some of the signal in tended for tracks 1 and 3 may get on or near tracks 2 and 4. Definitely have your deck checked and corrected by an authorized service shop.

(Audio magazine, Jul. 1980; Herman Burstein )

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