Advice on readers' technical problems.
By LARRY KLEIN, Technical Editor
FM Stress Conditions
Q. Since I do most of my listening to FM rather than records or tapes, I feel it is worthwhile to spend the money for a top-quality FM tuner. However, considering that FM tuners are now available at thousands of dollars each, how much money need I spend to get the results f want?
ABRAHAM KANTOR; Bethpage, N.Y.
A. This is a tough question to answer directly because of the many variables involved.
As with several other audio components, the major difference between a very good tuner and a state-of-the-art unit appears to be essentially in how well it performs under less than ideal conditions. For example, there may be large reflective objects in your reception area, powerful sources of r.f. noise and interference, or many high-powered stations crowding the dial. Or it may be that you simply want to receive distant stations with a minimum of noise. A better-than-very-good FM tuner will help you cope with these reception difficulties, although a good antenna with a good tuner may be of more help than hundreds of extra dollars spent on a super tuner.
It is certainly true that the new generation of fine tuners has much better channel separation and lower noise and distortion. Frequently, however, a fine tuner's potential audio performance far outstrips the quality of the signal being broadcast by most FM stations.
When a station transmits a compressed, noisy, frequency-restricted, distorted audio signal, the best tuner in the world can't do anything about it except simply tell it like it is.
Power Upgrade
Q. I'm using a 40-watt-per-channel receiver and I'd like to step up to a super-power 400-watt amplifier. Is it okay if I use my old receiver as a preamp and tuner, or should I trade it in on a new separate preamp and tuner? What would you suggest?
N. WONG Chicago, Ill.
A. If your present receiver has a set of A preamp-out/power-amp-in jacks joined by external jumper cables (or an internal switch), then remove the jumpers (or switch the switch) and install a pair of shielded cables from the preamp-out jacks to the inputs of your new power amplifier. All the controls on your receiver will function as before, except for the speaker-selector switch and head phone jack. You may have to set the volume control somewhat higher for a given loudness level, but this should be of no concern-it does not indicate lack of power in your new amplifier. If your receiver does not have accessible pre/main (as the Japanese call it) connections, your easiest course would be to trade in toward a separate preamp and tuner.
Definition of High Fidelity
Q. My question is short and simple: what is the definition of high fidelity?
ARNOLD MARKS; Pittsburgh, Pa.
A. I'm afraid my answer is going to be long and complex--mostly because there has never been any formal standard set in this country as to what constitutes high-fidelity sound reproduction. Like "beauty," high fidelity is an ideal: unlike beauty, which traditionally is said to lie in the eye of the beholder, ft does not reside totally in the ear of the listener, for it can be subjected to some objective evaluation.
High fidelity attempts to create the illusion of a "natural" sonic event by means of equipment not involved in creating the original sound. This is usually done by recording an original sound or sounds, simultaneously or separately, and then playing back the recording in such a way that a listener hears a reasonable facsimile of the way some original might have sounded.
If that definition seems somewhat vague, coming from someone who takes pride, as I do, in clear expression, it's because I've tried to cover all bases. For example, modern electronic music, when it is created directly into or with a tape recorder, has no original sonic reality to reproduce. As a matter of fact, if you want to hear the composition exactly as the composer intended (assuming that there was an intent in that area), then you must use the same speakers and amplifiers employed during his original playbacks in order to duplicate the characteristic breakups and overload distortions. This is particularly important in electronic music because most home audio equipment will be overloaded by electronic music played very loudly.
Furthermore, even using the finest avail able quadraphonic equipment and program material one cannot hope to reproduce in one's home the original sound field of the re cording studio(s), even assuming (it is unlikely) that the microphones originally captured it. Since the acoustics in the home are not the acoustics of the studio or concert hall, the acoustics embodied in the recording at best can only interact with the sonic situation in your listening room to produce a plausible facsimile of what the original musicians might have sounded like. And this can occur only when you are reproducing the sound of a small group; the larger the musical forces involved, the less real they are likely to sound in a conventional-size listening room.
During my approximately twenty-five years of involvement with hi-fi, I've heard the sort of "plausible facsimile" reproduction I'm re-referring to only four or five times-in other words, when I listened with my eyes closed, I could have mistaken what I heard for "live" sound.
None of the above should be interpreted as a put-down of the quest for high-fidelity. In a real sense we have already achieved high fidelity: what we are now after is absolute fidelity, and each positive advance in high-fidelity technology brings us another step closer to realizing it.
Switched and Unswitched Outlets
Q. I'm curious about the logic behind the use of the built-in switched and unswitched a.c. outlets found on the rear panels of hi-fi equipment. How does one know which to use for any particular piece of equipment?
STEVEN GORMAN; San Francisco, Calif.
A. The switched and unswitched labels refer to the fact that a component's un switched sockets will provide a.c. power as long as it is plugged into the a.c. wall socket whether it is turned on or not. The switched outlets, as implied, are turned on and off by the power switch on the component.
In general, the rule to follow is this: mechanical components that will be left "in gear" if switched off during play should be plugged into the unswitched a.c. outlets.
Straight electronic components (tuners, equalizers, etc.) that you may want to turn on and off with the main power switch should be plugged into the switched outlets. The reason for the unswitched outlets is that some equipment (tape recorders or record players), if switched off during play, might be left with a rubber idler wheel pressed against a drive shaft. If allowed to remain in that condition for too long a time, there's a chance that the idler will develop a flat spot or dent that may get audibly into the act the next time the equipment is used. What is "too long a time"? I don't know, but why take chances? Incidentally, a few readers have complained about the sparsity of a.c. outlets on some receivers. A cheap and easy solution to this problem is to make up a foot-long "extension cord" with an a.c. plug at one end (to be plugged into the single available outlet) and a four-socket "cube tap" on the other. You need not worry about overloading the extension as long as you don't plug a 700-watt power amplifier into it.
Because the number of questions we receive each month is greater than we can reply to individually, only those letters selected for use in this column can be answered. Sorry!
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Also see:
TAPE HORIZONS--Drop That Mike
CHOOSING SIDES, IRVING KOLODIN
NEW PRODUCTS--A roundup of the latest in high-fidelity equipment