AUDIOCLINIC (Oct. 1981)

His Mastered Voice

Q. When I was at a record store, I noticed an audiophile release of Bruce Springsteen's album Born to Run. The sticker on it said that it was mastered at one-half speed.

I am not knowledgeable about what this means in terms of my ears. (That is why I read Audio and I learn a little bit more every time.) I am really asking two questions: What does being mastered at half speed signify? Would I really need a good, high-quality system to be able to hear the difference?

-Eileen Margaret Pelton, Ft. Worth, Tex.

A. Most cutting heads do not "like" high frequencies. They do, however, find bass frequencies no problem to handle. Therefore, some studios have taken to cutting their master discs at one-half playing speed, with the tape recorder and the turntable both running at one-half their proper speed for normal sounding playback. The result during ultimate playback at correct speed is, once again, a perfectly normal sound.

Because the cutting head had an easier time of it at higher frequencies, the transparency is sometimes a bit better than that same disc would have had if the mastering had been done at normal speed. However, the use of the half-speed cutting technique does not necessarily insure a beautiful sounding recording. If the original tape was mediocre, the final product will also be mediocre.

The aural differences are subtle, but, if they can be heard at all, they should produce some improvement when played on even a moderately good sound system.

Equalizer Lacks Bass

Q. When I use my equalizer, one channel is fine but the other channel lacks bass. When I disconnect the equalizer, the bass comes back.

-Phil Ochino, Jr., Bronx, N.Y.

A. It seems that your loss of bass in one channel is caused by a defective equalizer. To prove this, interchange the wiring of the left and right channels of the equalizer and see if the problem moves over to the opposite channel. If it does, the problem is definitely in the equalizer. It should be serviced (I hope under warranty). The two most obvious causes of such a condition are either defective inter-stage-coupling capacitors or defective emitter-bypass capacitors. Poor soldering of the low frequency controls and circuitry could also account for the problem you describe.

Unheavenly Hash

Q. I am receiving bad "hash" noise from light dimmers. Noise can be picked up anywhere in our house using a battery-operated good-quality AM radio.

This hash is not heard on FM, and the sound of the hash varies as the dimmer setting is changed.

-C.E. Mervine, Palmyra, Pa.

A. The simplest solution to your problem is to get rid of the dimmer. Such devices are noted for creating exactly the kind of problems you described.

While it is sometimes possible to bring about improvement by using rather expensive, complex filters, you might install them and realize little improvement.

There is a device made by GE which can eliminate some "spikes" from the powerline, varistor No. MOV130 LA10.

You can write General Electric for more information at 727 Lynnway, Lynn, Mass. 01910.

Another more complex device, working more as a filter than as a peak suppressor, is produced by Corcom, whose address is: 2635 N. Kildare Ave., Chicago, Ill. 60639. These devices are designated as RFI Powerline Filters for low-frequency noise applications.

Devices of the latter kind, especially, must be placed at the source of the interference--the dimmer--if reasonable results are to be obtained. This often means that the installation must be done in the wall on which the dimmer is located, a somewhat troublesome process.

You may find it easier merely to use lighting provided by lamps that accommodate multi-power bulbs, such as 100/200/300 watts, etc. Thus, various light intensities can be achieved without using an SCR dimmer. A "Variac" can be used as a dimmer with the understanding that it is somewhat cumbersome physically. However, it is efficient and will not produce the heat build-up associated with a rheostat.

==============

(Audio magazine, Oct. 1981, JOSEPH GIOVANELLI)

= = = =