Tape Guide (Q and A) (Mar. 1970)

by HERMAN BURSTEIN

Tape Squeeeeeaal!

Q. I would appreciate your advice on a perplexing and frustrating problem which has occurred in connection with my tape recorder. I have two tape decks: °°° which I use primarily for recording and a °°° which is used almost entirely for playback of prerecorded tapes and my own tapes. Both machines are less than six months old. A month or two ago I noticed a loud squeal coming from the ° ° ° when I played tapes which I had recorded on the ° ° ° a This was audible not only as a mechanical noise which could be heard easily in the next room, but also through the two speaker systems of my stereo system. The music on the tape became harsh and distorted.

When I cleaned the ° ° ° °'s heads, the squeal subsided for a short time, but soon came back. When I transferred the tape to the ° ° , there was no squeal. Assuming that the fault lay with the ° ° °° , I returned it to the audio dealer from whom I'd purchased it for repair. He loaned me a tape recorder of still another make to use while the ° ° ° ° was being worked on. The serviceman was unable to find anything wrong with the ° ° ° °, and the squeal, needless to say did not occur while it was in the repair shop. In the meantime, it did plague me again, while playing my tapes on the third machine loaned to me. Aha, I thought! It's the tape! This argument sounds good, but has several holes. First, I am using 1 mil polyester low-noise tape made by a top company. Second, this tape is supposed to be permanently silicone lubricated. Third, why does the squeal occur only after the deck has been operating for some time? Fourth, why can't I hear it every time I play the same spot on a tape; sometimes I can play a tape through with no problem. Fifth, why is there no squeal when I play the same tape on the °°°° or when I'm recording? Last, I can make the squeal stop by reversing the direction of play. As you can understand, this is the sort of problem which has me tearing my hair out. I would be most grateful for your help.

-Stephen Sarper; Pittsburgh, Pa.

A. I do not have an explicit answer for you. I have heard, though, that certain tapes in combination with certain tape machines are apt to result in squeal. And not always; the squeal may come and go with temperature, humidity, how long the machine has been running (and therefore how much heat has been generated), how many times the tape has been used, when the heads and guides were last cleaned, etc. etc. The fact that a given tape may squeal on one machine and not on another may have to do with the tape tension system employed, the pressure pads used or not used, tape approach to the heads, location of tape guides, etc. It is difficult to get down to specific rules as to what does and what does not cause squeal. The best course is to try various kinds, and brands of tape until you find the one that works best with your particular machine or machines.

Undistorted 'Rock'

Q. On occasion I have recorded a live "rock" group and have found it fairly difficult to get a clear undistorted tape. I have placed mikes among the performers and as far away as 20 feet without the hoped-for results. Does room size and sound intensity need to be taken into account? I recorded one group in a large, acoustically terrible auditorium and got better results than in a smaller ballroom, although there were unwanted echoes in the auditorium. I have used several different mikes with about the same results for all. Can the input of my tape recorder be overloaded and still allow the VU meter to read the correct level? Would volume controls between the mikes and tape recorder help the distortion, or would it merely provide different balances? Is there any way to connect directly to the performers' amplifiers, or is this undesirable? In short, is there any way to eliminate the unwanted distortion from my recordings?

-Ben Miller, Barrington, Illinois.

A. My guess is that you are overloading your tape, particularly if there is a considerable amount of treble in your "rock" group attributable to female voice or instruments.

It is quite possible for a tape recorder meter, VU or otherwise, to understate the actual level of the signal reaching the tape by as much as 10 to 20 db. One reason might be mis-calibration of the meter. More likely is the fact that the meter, because it is a mechanical rather than electronic device, cannot follow the rapid, high amplitude, brief sounds that we call transients. And this is even worse at high frequencies due to the large amount of treble boost supplied by the tape machine's record amplifier. I suggest that you back down on the record volume control of your tape machine, even though the VU meter is then reading considerably below 0 VU. Of course, the possibility still remains that your tape recorder has a poorly designed first stage that overloads too readily. Finally, it is possible that you are using a poorly designed microphone that overloads too readily.

What Deck Shall I Buy?

Q. I want a tape deck for recording and playing music, and am willing to spend around $500 if necessary. Do you have any recommendations? Despite many months of searching through equipment reports, the vast profusion of tape decks on the market today (most of which have not been tested by any of the high fidelity organizations) make a decision extremely hard.

-Brian P. Cox, Philadelphia, Pa.

A. I repeat--and repeat and repeat--that the policy of Audio magazine strictly prohibits me from recommending specific items of audio equipment.

Confusing as they may be, equipment reports are one of your very best guides to a tape reorder suitable to your requirements and purse. Although the specific model you see in a store may not have been reviewed, the chances are that similar models of the same manufacturer have been reviewed and you can be guided accordingly. Also, do not hesitate to trust the evidence of your own ears when you listen to a tape machine in a store.

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If you have a problem or question on tape recording write to Mr. Herman Burstein at AUDIO, 134 North Thirteenth Street, Philadelphia, Pa. 19107.

(Audio magazine, Mar. 1970; Herman Burstein)

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