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Hiss & Scratch Remedy
Q. I have a lot of recorded tapes but they have too much hiss and scratch.
Would it be worthwhile to record these tapes over on a special low noise tape?
-Mark Gedler, Atlanta, Ga.
A. I am not sure what you mean by recording your tapes over. Do you mean going back to the original sources, such as phono discs? Or do you mean copying your present tapes on low-noise tapes? If you have in mind going back to the original sources, it may be that these have excessive hiss and scratch. Then the use of low-noise tape will not improve matters. Perhaps you have been under-recording so that the noise of both your tape machine and the tape are relatively prominent compared with the desired audio signal. If so, an increased recording level-short of noticeable distortion-might be your best answer. Shifting to low-noise tape may add a slight improvement.
But, if you have in mind the copying of your present tapes, you will be copying the noise along with the signal, so copying onto a low-noise tape will not help. However, you might check with local audio stores as to what single-ended noise reduction systems are available.
Q. The digital timer on my tape deck shows only the approximate positions of the recording, but it does not have the accuracy of a movie camera footage counter. Isn't there a way to calculate the time the tape will cover as I often run out of tape before the program's end. Is there any device which measures the tape length?
-H.S. Liu, Los Angeles, Cal.
A. Some time ago a device to measure actual tape footage was brought out but it wasn't a success. It was meant to be attached to the tape deck, but this was a rather clumsy arrangement. Most people are satisfied to find the approximate portion of the tape reel in which they are interested.
A seven-inch reel of conventional tape runs 32 minutes in one direction at 7 1/2 ips, and 64 minutes at 3 1/4 ips.
The times are increased by a factor of 50 percent for the 1 mil tape, and a factor of 100 percent for the 1/2 mil tape. Thus, you can use a timing device such as a photo timer, wrist watch, kitchen timer, etc., to tell where you are and how much time you have to go.
Way of Wear
Q. Will a tape deck with bi-directional operation wear the tape heads faster than a unidirectional deck?
-Dan Moyer, APO, San Francisco.
A. A properly designed and constructed tape machine that operates in two directions will not impose extra wear on the heads.
Q. I have a very strong permanent magnet which I use on board my boat for retrieving metal objects dropped overboard. I also have a cassette tape machine board with a goodly number of cassettes. Since there is always the possibility of these coming together in storage, is there some way I can shield them against each other?
-R.J. Stephenson, Chattanooga, Tenn.
A. I suggest you write for information about shielding material to Magnetic Shield Division, Perfection Mica Co., 1322 N. Elston Ave., Chicago, IL 60622
Q. I will be recording in the field and would like to ask your advice about microphone selection. Would you say that a capacitor type mike would provide significant improvement over a dynamic one in the same price range?-James Donovan, Marblehead, Mass.
A. Apart from the question of price, capacitor microphones are generally regarded as superior. But when they are in the same price range as other types of microphones, this superiority may vanish. For use in the field, it is undesirable to use a ribbon mike because of its susceptibility to wind noise and its generally greater fragility. Dynamic mikes are generally the most rugged. Perhaps you can find an accommodating dealer who will let you try out two or three microphones to determine which is the best for your purpose.
Q. A dealer offers Scotch low noise tapes at less than half price. He says they were used by studios and erased, which in no way affects the sound quality. Can this be true? If the sound isn't affected, why does the studio discard the tape?
-H.S. Liu, Los Angeles, Cal.
A. If the tape is indeed Scotch and has been used only a few times, it seems that you would be getting nearly the equivalent of new tape-unless the tape has been spliced for editing.
Spliced tape would be the studio's reason for discarding it.
Q. My tape recorder operates at 7 1/2 and 3 3/4 ips. I compared the sound at the two speeds and couldn't detect a difference. The dealer told me the higher speed only extends the range beyond 12,000 Hz which is above my hearing range. My friend said that 1 should use the faster speed to get full use of the machine.
-H.S. Liu, Los Angeles, Cal.
A. The advantages of the higher speed, in addition to better treble response, are somewhat greater signal-to-noise ratio and less chance of distortion at the higher frequencies.
Q. My Sony mixer is equipped with VU meters. These show the output signal and are affected by the master gain control. How are these to be used in correlation with the VU meters on my tape machine. So far, I have just used the mixer to set the relative levels on the microphones and have adjusted the master gain so the pots on the tape recorder don't have to be advanced more than two-thirds of maximum. Could you tell me the correct way to use them?
-Howard Sanner Jr., Hyattsville, Md.
A. It would appear to be a good practice to adjust the master gain control of your mixer so that whether the microphone is fed directly into the mixer or directly into the tape recorder, the same setting is required for the record gain control of the tape machine.
(Source: Audio magazine, Jan. 1977, Herman Burstein)
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