As I continue these days to listen intensively to stereo FM at a DX-ing distance
of 100 miles something I have not tried for a long, long time (see last month)
I am forcefully reminded that the very earliest stereo broadcasts were simulcasts
at full strength, out of two separate stations, each offering its normal mono
coverage. Like a pair of locomotives hitched to a double length train. For
if we were to send out two signals, should not each cover the same area in
signal strength as one alone? Reasonable thought! But, alas, not now the case.
Present stereo coverage, two channels via one carrier, is weaker than the equivalent
mono broadcast and goes out a lesser distance in useable form. And yet here
I am 100 miles away and listening in stereo. Without pain. We do progress,
in spite of necessary compromises.
The early experiments didn't always work. Often one station was FM, the other AM, a matter of practicality.
How could you listen, say, to an AM right channel, noisy and severely limited in frequency range, and an FM left channel, both noiseless and wide range? The mix, as I well remember, was awful. A few FM-FM experiments were set up in California, as I remember and here the stereo was good and strong too. Perhaps better than we shall ever get now in respect to full coverage and noise-free reception, both channels. But this couldn't last. You could hardly expect a working FM outlet to operate on only half a signal, one-sided. There had to be a better way, two channels from a single station. And the pure engineering voice who told us how to do it via multiplex was Murray Crosby, a man who would not compromise short of the ideal merely to accommodate existing SCA subcarriers.
Well, Crosby lost out and SCA is still alive and occasionally with us. Our present stereo system is a somewhat elaborate compromise designed to take on, when necessary, more than the basic two channels, which leaves our stereo broadcast power somewhat under strength but basically pretty much OK, now that we have learned to live with it. But stereo coverage is apt to be weak in the outskirts and easily subject to noise interference, as plenty of us have discovered.
At 100 miles, I never earlier could listen to stereo on the air. Mono came through beautifully stereo was mostly a roar of .noise, a background sound so harsh and so cutting to the that could not take it for long. It was a nasty and distressing choice for a switch to mono brought instant peace, low noise, and inevitable boredom. Who wants to listen to mono? That's for portable transistors. I hated to miss something that I knew was right there, the full ambience and separation of two-channel broadcast sound. So near, and yet so far. Stereo, for me, at my distance, was a bust.
I say this because now for the first time, during these last months, I have at last been able to listen regularly in stereo and really enjoy it. Now, at last, in the current generation of FM stereo tuners, the noise is under control. Not counting, of course, passing interferences like planes, vast numbers of them and who knows how far away, bringing great pulses and gasps of the old familiar roaring, slow, then faster and faster as the reflection interference angles change .... But the planes are merely a nuisance factor. They come and they depart, and all is well.
At my extreme range, my new tuner brings in numbers of very distant stereo stations with no more noise than many a disc and tape I play via the same equipment. But this isn't all in the way of improvement. There's something else that has me intrigued ... the remaining noise no longer harsh. It has, somehow, been gentled that's the best word.
Instead of the old barbed, sawtoothed FM-stereo roar, variously loud but always unpleasant at any level, there is now a smoother, more lubricated sound, altogether inoffensive when the signal strength is good as it often is. Amazing! I mostly don't mind it a bit. Which makes real stereo listening quite possible, almost restful, via distant stations as well as those that are (relatively) nearby, say a mere 40 miles off. That's good news. I am unable to explain the lubrication, but it is there. Better a lubricated noise than sawtooth, any day, even if ideally there should be no background noise at all.
So let us forget the theoretical arguments, for we have our chosen system well in hand and we are improving its compromise by, literally, leaps and bounds ... 100-mile leaps. Even Murray Crosby might be impressed at what we now can do with stereo.
Yes, I know. I will be assured, by those who know, that I am wrong. Under correct reception conditions there is no stereo noise. Well, I'll agree for city or suburb listening. I have often heard it, so to speak. Especially when the music is background and the level turned down. But even with louder music there seems to be no noise or is there? Do not forget that in the city there is a steady and subliminal background spectrum of "live" sound that can easily mask any slight residual noise in stereo reception. Even on a Sunday morning or in the wee small hours of the week. City FM listening is not an objective test. Very useful illusion, though, for city listeners.
Hi-Fi Coconut
Where I live, there is no masking, unless occasionally the wind sighs in the trees. Moreover, I like my music LOUD, just like any seasoned hi-fi coconut. If there's any residual noise at all, I'm going to hear it, and I do. It's there! Always. But I really don't mind much any more. Nor will you.
So put residual noise aside and look at stereo FM itself, in case you are newly interested, out there in your own country spot at a distance from the stations of your choice. With your brand-new hi-fi tuner don't even think of trying an older one, however good it was in its time you may perhaps get what you want via a rooftop directional TV antenna, which doesn't filter out the FM that is right between the two principal TV bands. A genuine FM directional is a better idea, space allowing, and the bigger the better, of course. I'm going to have to get me another rotator; you will need one if your stations are off in various directions. 'Nuff said. just feed into your home hi-fi system and it will be happy and so will you, maybe even at 150 miles out. Possible, these days.
I've been fascinated at the current goings-on across the FM spectrum, as compared with some years back. Numberless new, loud, pop stations.
As I tactfully suggested last month, I skip hastily over them, however worthy the listening from some people's viewpoint. (Not many of these people are hi-fi coconuts.) But I do find myself asking, how much of that hideous (?) distortion is artistically deliberate and a part of the musical effect? Quite a lot, and we must respect this even if we don't ourselves jive and bounce to the disco beat. If the station adds a deliberate bit more distortion
who's to complain? You can skip it ... I skip it.
There are dozens of other stations, other types, to keep me perpetually busy that's one great advantage of a distant country location, where you get a real overview, or underview, of the radio scene. I also mentioned muting circuitry, the usual way to cut out inter-station noise. Not much use in the country, it cuts out many stations too. This Pioneer's is in two fixed positions, and just for fun one day I put it into the extreme muting position, No.
2, just to see which stations would get through. Only the strongest can make it, normally the nearby locals. The rest are suppressed. Well, I have no nearby locals. But on this extreme muting I went down the dial and counted no less than 27 stations that made it past the mute, not one of them nearer than 40 or 50 miles. How's that for a choice? When I tried the milder No. 1 mute position, I picked up no less than 50, unmuted. Many more showed up on the signal-strength meter, though silent. Definitely, some of these, too, minus mute, are listenable, in mono if not in the noisier stereo, in case you really find something you want to hear. I often do. I suspect that with a rotator I could increase this vast station roster by a dozen or so useful outlets, if I ever had the time to listen to them. Thanks to narrow-band reception (alternative to the top-fi, wide-band circuit in Pioneer) and to extreme sensitivity, a large proportion of these many and closely packed sources are now at least marginally listenable, and there is very little of that disastrous overlapping of signals I used to experience.
[...] that matter, in the million $$ disco type of sound reproduction. This is entirely legitimate, I say, and the only question is, what should a stereo FM outlet do? Just play the things, and let the mono fall where it may. As we all know, mono sound in pop music can be pretty spectacular.
I note, by the way, that there are definitely different artistic techniques in the use or non-use of separation, from one pop disc to the next interesting to watch, especially on a four channel decode/enhance system like mine. The decoders are extremely sensitive to these differing techniques.
The back-speaker meters react most strikingly and differently. There are, for instance, many pop discs which have a sort of two-way vertical mono, the right-channel meters moving in step, the left-channel pair also in step but differently. Oppositely, there are those which have horizontal mono, the top or front meters moving together, the bottom pair, the back channels, moving also together but differently. (Pure mono makes them all move alike.) You can get a load of some of this with your own eyes if you have a stereo tuner and available meters use your tape recorder. Quite fascinating.
Interview-type Stereo One thing that distresses and perplexes me is the lack of any useful stereo in the interview-type or roundtable program of speech. There's the stereo light, on as usual. And both speaking voices, or all four or five, come vaguely out of dead center without the slightest trace of spatial location or separation. Why, Why? It would seem to me that a multiple voice speech program is the obvious place for good use of channel separation. Is it mere lack of imagination? Is it the technical need for compatibility with mono reception? (If so, then why bother with a stereo transmitter at all.) Is it, perhaps, partly a problem of transmission via the complex stereo broadcast circuitry, which (I am speculating) may not appreciate severe separation between channels? Some of you broadcast engineers might let us know your thoughts on this. I can only say that on occasion I have heard my own voice broadcast 90 percent in one channel though in phase from a single mike without problems, even against a full stereo spread of music. If there had been two of me, surely I would have put one in each channel for a right-left dialogue. But would I have been in trouble with the broadcast engineers? (Later, I shifted to 5050 mono, into the two channels, but only because the center position was aesthetically better for the program.)
Collegiate FM
I could go on .... I haven't even started on my favorite sort of FM in this new round of listening, the student-operated university station. Such fun! Such knowledge and enthusiasm, such marvelous goofs and gaffes! Naive, but brilliant too. These stations mostly began 'way back as in-house affairs, carrying a city block or so, but today they often are full-power public outlets audible to millions. A real responsibility for young students. Some stations have gone stuffy, or conventional, but others retain a freshness that is wonderfully needed today in FM. At 100 miles I can pick up no less than three of these in the New York area. My favorite for its combination of solid and interesting programming with the most delightful faux pas -- many laughs -- is Fordham University's WFUV (90.7), 24 hours a day a lot for volunteer labor and in stereo, too, with a beautiful clear signal and excellent presence. You're right in the studio as you listen. Or rather, these kids are right in your own living room with you. Enjoy! Even at 100 miles.
(Source: Audio magazine, Apr. 1979; Edward Tatnall Canby )
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