Audio Etc. (April 1984)--CHRISTMAS CARDIOIDS

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Did I seem to end on a pessimistic note last month? I was talking about loudspeakers in consumerland, and the micro-mouse squeak.

Sorry--I just can't take this subliminal background music I hear all over the place these days. All that beautiful, ex pensively potent hi-fi, so delicately de signed for making big noises out of small signals, emitting nothing but barely audible chirps, just enough to register on the non-listening ear! Reaction from decades of loud volume, the earlier form of hi-fi status? Probably.

After all, if one generation wears beards, the next has to be clean shaven, as even the Romans knew, minus electric razors. So did George Washington and Thomas Jefferson. Then there were beards again, and then there weren't, and now there are. Can hi-fi be different? Down with loud volume. up with micro-squeak.

At the other end of the audio chain (see last month), it is good to know that the microphone can never be a macro-phone. Its rep for useful but totally in audible sound is permanent. There isn't much scope for status display in any sort of mike, even with chrome and plastic. Much less in TV gray or black or dirt brown. Mikes are not for looking at. Yes, I know, pop stars often sing into a hand mike that is totally dead, using it merely as a required prop ever notice how they sometimes wave it around in the air (which would pro duce outlandish results if the thing were really functional)? But mikes in general are sober devices and largely practical, just a means to an end many remarkable ends. With apologies to the speaker people, I find the mike part of the audio chain much more interesting. Both mikes and speakers are transducers functioning in fields of actual sound, but the range of effects that we can get with our present art of microphoning is absolutely astounding. No lesser word will do.

While loudspeaker designers still work enthusiastically to pare down distortion, flatten peaks and dips, align phases, polish up the TIM (only to launch their marvelous products into the current mouse-squeak void), the mike folks after 60 years are still jubilantly developing whole new kinds of mikes, and new ways of using them which leads to larger things, such as the ever-new recording studios, or those enormous mixing boards you find in every one of them and assembled in booth after booth at the AES shows. To me, those giant boards are blurs of knobs and sliders by the mil lion, as awesome as, maybe, a grand piano 20 feet wide with a thousand keys to play on, but to mike users they are familiar tools. At the shows, high school students talk over their fine points in the most casual fashion, as though it were all very simple. (It isn't.) Such is the power of the microphone.

As a youth, I never set eyes on a mike, though I had played my own baby records on a wind-up machine long before. Even in the blossoming times of the Orthophonic phonograph, still acoustic but with a folded exponential horn, big volume (relatively) and lots of new bass (I was about to write: Also the Brunswick Panasonic but of course meant the Brunswick Panatropic)--even with these and the electrically recorded Orthophonic re cords and other equivalents, we had only the vaguest idea as to what a microphone was. The horn was gone; if you had music to record or broadcast, you set up this small square wooden box in front of it, and the music came out of your radio at home. How? We didn't much bother. Or, presumably, it could also go directly onto a shellac disc; we were foggy as to any necessary steps between. Somehow, course, these discs multiplied like the brooms in "The Sorcerer's Apprentice," and we could all play records, but this aspect didn't bother us either.

It was broadcasting that put the mike on the map. There never had been a horn in that area, and the microphone was essential from the beginning for everything but Morse code. Shure Brothers recently sent out a lovely Christmas card with a group of elderly Shure mikes on its cover. If you are my age you will know them all, but the one that instantly stands out is of the type that virtually became a symbol for broadcasting when radio finally went big. It's a sizable metal ring on a stand with a symmetrical set of springs inside holding a round mike suspended in the middle, presumably shock-proof. That was the idea, anyhow. Shure's was a carbon mike, the 33N of 1932, following the well-established transduction system of the telephone, going far back before the turn of the century. For years, every photo of a radio star or broadcasting group would feature a similar mike in the foreground, more as a symbol of the broadcast art than as a practical transducer. If an ordinary citizen were asked to draw a picture of a mike during those years, he would have immediately produced a circle with the elegant springs inside, and a blob for the mike itself. That's the way a mike looked.

New shapes, though, were coming in along with new types of transduction. Shure's other mikes of the 1930s are familiar still, in their looks and in principle too-the crystal mike, a small round thing minus springs, and also in the fancier blunt-bullet shape (the 720B) which I remember as the ultimate in elegance. Note that these mikes were generally chromed and nickeled, to impress live audiences and to look great in press pictures. All that came to an abrupt end with TV, which could not use any microphone that visibly reflected those huge over head lights.

What happened to the springs? Dare I surmise that, just maybe, those high-style chromed suspenders created a vast collection of spurious resonances, right at the mike itself? Think of all the spring-fed reverb units we have used during these later years. In any case, the handsome spring mounts were no longer to be seen on the scene after the mid-'30s. A much better idea for solid protection, though I wonder how the slots were designed, came with the die-cast mike housing, a style that remained good looking and useful even in dun-colored brown, as in the famous Western Electric cardioid, combining dynamic and ribbon elements. Shure's 556B, on that same Christmas card, was long familiar in semi-pro and studio recording. That version dates from 1938, a dynamic. You will note that numerous mike manufacturers made use of these different visual styles, the way the car makers borrowed back and forth in auto shapes, in radiator grilles and fenders. It's not at all a coincidence, I'd say, that the die-cast microphone coincides in date with the equally handsome die-cast automobile grille.

One mike on the Shure picture is really unfamiliar, an early condenser.

The 40D of 1935 is an ungainly tall black container with a round mike element mounted rather clumsily on top.

In those big-tube days, the necessary extras to polarize the diaphragm and process the signal were hard to de vise. A much more familiar, and much later, "early" condenser mike comes immediately to my mind-I bought one for myself: The wine-bottle Altec, a tall, thin, graceful black shape with a really tiny (for the time) active unit on top.

And, alas, an enormous power-supply box plus the most unwieldy thick cable I have ever dealt with. Nevertheless (and in spite of an often cited peak in the high end), it was sensational in its day and I have a story to tell that some will remember. When stereo came in, all resplendent in its two channels, the AES banquet, not to mention every thing else in sight, was duly dual-equipped, two of everything. If I am right, then, the human speakers at that banquet faced not one but two mikes, one to each side, with sets of "PA" loudspeakers banked at each end of the hall. The effect was disastrous.

Each time the dinner speaker moved his silly head a quarter of an inch (and how many of our fine engineers have yet learned that before the microphone you do not move the head?), the sound source jumped 50 feet sidewise. It was a sonic battleground with Presidents, V.P.s, Honored Guests, all flying through the air at terrifying speeds from one end of the room to the other.

As I remember, the pairs of mikes in use were "bottle" Altecs.

Not having 50 pages at my disposal, I will gently skip the next quarter-century and more of microphone history in favor of a couple of relevant items from the present, where the furor over mikes and mike techniques is continuing as forcefully as ever in the past. First, a new note on the now-celebrated PZM, which this department touted a couple of years ago as a basically new micro phone type in its characteristics and pickup pattern, a half-sphere. Since Crown took up the PZM, its use has spread and so has experimentation, mainly, but, I gather, not exclusively with Crown-made equipment. (The mike originated at Syn-Aud-Con via the work of Ed Long and Ron Wicker sham.) It's my impression that for most of this period the PZM has been used in variants of its original configuration, a tiny capsule mounted in the zone of equal pressure within a millimeter or two of a flat surface-that surface being anything from a smallish plate (weak bass) to the lid or "wing" of a piano or harpsichord, even a whole wall, or the floor, or a table top, any thing with enough flat space to do the required job, similarly to a flat speaker baffle. Most enterprising usage has been the hanging plastic rectangle with the microphone at its center, giving a horizontal hemisphere of re response on one side and virtually none on the other. Not like any other configuration of any common sort.

But the PZM hasn't fitted into the now-common forms of stereo pickup, except in the form of two spaced plastic mounts. Down in Texas. Michael Lamm and John C. Lehmann of the nicely named Dove & Note Recording Co... working largely in classical re cording and broadcast, including TV, have devised an ingenious new geo metrical complex of plastic mounts and Crown PZMs that can simulate or, better, duplicate the conventional pick up patterns for stereo that are now widely in use with standard micro phones. Mr. Lamm first phoned me about a Christmas TV Messiah, emanating from Texas, that used a specially built array named the L2 MicArray, and at last fall's AES convention they gave a paper on their system. Unfortunately, I missed it thanks to the Transit Authority--I stood on a 42nd Street subway station waiting for a non-existent train. But there is a preprint. No. 2025 (C9), which describes this array.

It is an adjustable package of clear plastic panes which can be mounted around two PZMs at various positions and angles to produce the typical pick up patterns of an astonishing variety of stereo alternatives M-S, DIN. X-Y, and many more initials. As usual, I'll keep my non-engineering hands clean and go no further into the details. But the system strikes me as full of interest for classical experimenters and for the latest in pop styles as well, those that are simplified a bit from the usual forest of microphones long standard at pop sessions. No. I assume you will not be able to use 30 PZMs in the L2 MicArray. For information, you might try Michael Lamm at Dove & Note Re cording, 15415 West Antone Circle, Houston. Tex. 77071.

Finally, I mentioned a new type of microphone, mounted like a PZM in plastic rectangles, at the 1983 Bach Festival in Eugene, Ore. It is, rather, a new application of an old principle, using miniature capsules in the PZM manner but in a different way altogether, the flush mount. This capsule is mounted face up, virtually flat against the large Plexiglas rectangle, rather than pointing down towards the flat surface. Messrs. James Swirczynski and Steve Hangebrauk of JES Audio Design (see Dec. 1983) are experimenting with demountable inserts so that direct comparisons can be made between PZMs and the flush-mount capsules in the same format and. I assume, with very nearly identical pickup patterns.

It would be interesting to bring these two operations together the L2 MicArray and the flush mounts, perhaps?


(adapted from Audio magazine, Apr. 1984; EDWARD TATNALL CANBY)

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