TAPE GUIDE (Oct. 1983)

Recording TV Sound

Q. I would like to record TV sound on my cassette deck. Do I need some kind of adapter? Do you have the names of manufacturers?

-Pongsak Srisa-an, Syracuse, N.Y.

A. TV audio tuners-that work in the same manner as AM or FM tuners, but on the VHF and UHF channels have been made at one time or another by Radio Shack, by Pioneer, and by a company called Rhoades National Corp. ( P.O. Box 817, Hendersonville, Tenn. 37075). I gather that the Radio Shack and Pioneer units have been discontinued, but some may still be around. I don't know about the Rhoades unit, but you might write to the company.

Another way is to take the TV sound signal from across the hot and ground leads of the TV set's volume control. Shielded cable should be used to connect from these points to the deck. However, this should be attempted only if the TV set has an Isolation transformer. Otherwise the connecting cable may be carrying a potentially lethal power line voltage.

The least satisfactory approach, but one that works for some, is to set up a mike in front of the TV speaker.

Too Much High Frequency

Q. I want to transfer a vocal disc onto cassette. One of the songs is much too abundant in highs. I've been thinking that there might be a gizmo I could connect between the output of the amplifier and the input of the cassette deck to reduce the highs. However, I don't want to spend too much, naturally, to cut the highs for just one song. I have tried recording this song with Dolby off and playing it with Dolby on, but this didn't help much. Can you suggest anything?

-John Scapelito, Fort Lauderdale, Fla.

A. Ordinarily, one would employ a graphic or parametric equalizer for this purpose, but these aren't exactly inexpensive. There is, however, one simple approach which might work for you, and it is cost-free. This is to increase the bias beyond the amount normally required for the tape you are using. An increase in bias reduces the high frequencies; it may also increase distortion, but not necessarily to an objectionable extent. For example, if you use ferric-oxide tape (Type I), set bias in recording for Type II (chromium dioxide and ferri-cobalt); this will substantially increase bias and cut the highs.

Mikes for Organ Recording

Q. I am planning to purchase a pair of microphones and would appreciate your suggestions. I will use these to record live classical pipe organ and choral music.

-David R. Lenington, Towanda, Pa.

A. Only some general suggestions can be offered in this space. First, you may prefer an omnidirectional mike to a cardioid one for at least two reasons:

For a given price, an omni usually has smoother frequency response, and it will pick up more hall ambience (assuming that's what you want). Second, for organ you will want a mike with extended low-frequency response.

Third, you should assay whatever mike you select on a trial basis, because it is difficult to tell in advance just how well any given mike will work in specific circumstances and with specific objectives in mind.

Open-Reel Decks with 1 7/8 ips Speed

Q. Why don't open-reel deck manufacturers bring back the 1 7/8 ips speed on their equipment? With the growth of noise reduction units, better electronics, and better tape formulations, it seems that the manufacturers could improve their decks' performance at this speed.

-Robert Patterson, Des Plaines, Ill.

A. True, the substantial majority of home open-reel decks do not provide the 1 7/8 ips speed. However, some do: Akai, Sony and Telex-Magnecord listed such models in Audio's 1982 Annual Equipment Directory issue, and ASC, Ampex, Revox and Uher have such models listed (elsewhere in this issue).

It may be that most of the manufacturers felt that those who want 1 7/8 ips will simply turn to cassette decks, particularly since good performers can be had there for as little as $300 or even appreciably less. On the other hand, when you consider the high price of the really top-quality cassette decks often rivaling or exceeding the price of good-quality open-reel decks-you realize that excellent performance at 1 1/4 ips isn't all that easy to achieve. Unless one uses the quite expensive metal tape, cassette at 1 1/4 ips offers relatively little headroom (freedom from tape saturation when recording high frequencies at high levels); this is particularly significant when recording live material. But at the 3 3/4 and 7 1/2 ips speeds most commonly found in open-reel decks, there is usually ample headroom. Further, the slower the tape speed, the greater the treble loss due to a given degree of azimuth misalignment (although Nakamichi, in its Drag on cassette deck, appears to have found an elegant-if not inexpensive solution to the problem of azimuth mis alignment). And still further, as tape speed is reduced, the gap of the play back head must be made correspondingly narrower in order to preserve high frequency response, which again costs dearly.

One-Pass Noise Reduction

Q. My problem is background noise on cassettes. This is not due to my tape system, which contains Dolby C noise reduction, but is part of the in coming signal from a remote FM station. I assume that a single-ended (one-pass) noise-reduction device could help me. If so, please provide a listing of such devices.

- Gabriel Katona, New York, N.Y.

A. Yes, a one-pass NR unit could be helpful. The answer to the rest of your question lies in the November 1982 issue of Audio, which contains a directory of such devices and the addresses of their manufacturers. Detailed in formation about units of interest to you can be obtained by writing to the manufacturers, who can also supply you with names of dealers in your area.

Dolby Mistracking

Q. When playing cassettes that I re corded in Dolby, the highs disappear. But when I switch off the Dolby, the highs return. What is the problem?

-R. P. Murphy, Milwaukee, Wisc.

A. Dolby works on the principle of boosting the high frequencies in re cording (the lower the signal level relative to a reference level, the greater the boost) and cutting the high frequencies in playback (the lower the signal level relative to a reference level, the greater the cut). The treble cut in play back matches the treble boost in re cording, thus restoring flat response, and at the same time reduces tape system noise, chiefly in the treble range.

It seems that the Dolby system in your deck is not working properly, either in recording or in playback or both. That is, the system may not be supplying sufficient treble boost in re cording, or it may be supplying excessive cut in playback, or both. Such mismatching is called mistracking. On the basis of the reference level, a Dolby system must be properly calibrated so that treble boost in recording and treble cut in playback are equal, thus producing flat response. It appears that the Dolby system in your deck is either mis-calibrated or defective. I suggest that you return your deck to the place of purchase or take it to an authorized service station.

Cassette Track Format

Q. I have a portable mono cassette deck and I play mono tapes through my audio system, using a Y-connector to feed both channels of my system's amplifier. If I were to play a stereo cassette tape through this system, would both tracks of the tape be picked up or only one track? If I had a stereo cassette deck, could I still play mono tapes and have the sound come through both speakers?

-Rudolph Feitl, Dumont, N.J.

A. The standards for mono cassette recording state that Tracks 1 and 2 the upper two tracks out of the four shall be used in one direction of operation, and Tracks 3 and 4 (lower two tracks) shall be used in the other direction. The standards for stereo cassette recording specify that Tracks 1 and 2 shall be used for stereo in one direction, and Tracks 3 and 4 in the other.

Accordingly, if you play a stereo cassette on a mono deck, you will be playing both the left and right channels. If you use a stereo cassette deck to play mono tapes, each section of the stereo head will pick up the same signal, which has been recorded on both Tracks and the island between.

Which Deck Gets the NR Unit?

Q. I own an open-reel deck and a cassette deck, and one dbx noise reduction unit. Should I use the dbx with the open-reel or cassette deck?

-Emil Garlitz, Jacksonville, Fla.

A. If you can use your dbx unit only with one deck or the other, it would probably be most effective when used with the cassette deck. The general principle is that noise reduction devices are most effective when used with equipment that can use the most help.

(Source: Audio magazine, Oct. 1983, HERMAN BURSTEIN)

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