There's nothing like a vacation, totally removed from audio, recordings, hi-fi,
et al., for garnering ideas to put in this space. Must be my karma, or my what-have-you.
Ideas look for me. I don't lift a finger. Like, say, PZM. I'd been hoping for
many months for a chance to witness these revolutionary new microphones in
action. So last July I went away from the Eastern steam-bath climate for my
annual concert binge, live, in the superb climate of central Oregon. And there
they were, right in front of my vacationing nose. Bullseye.
It was the 12th annual Oregon Bach Festival in Eugene (I went last year too) under the German choral conductor Helmuth Rilling, and I managed to take in three concerts a day for a couple of weeks, live--and I do not mean live on tape. I was there, body and soul, the complete music listener again, and who ever heard of audio? Not my hosts and concert neighbors! We were all immersed in a special Bach experience, with trimmings, and I fairly basked in the lovely emanations of live music. Phew! A free concert at noon each day and a bigger one each evening, not at all free.
Then at 5:15 each weekday Helmuth Rilling expounded "live" on a Bach Cantata, a new one every day, with musical illustrations direct from the chorus, orchestra and soloists. An experience almost unique in the world of Bach. After Herr Rilling's absolutely fascinating analysis-with-music, the whole Cantata would be done straight through, a half hour or so, each movement conducted by a different student conductor; for this was a triple-purpose event, not only a lecture-concert but also a sort of examination in public for a conductors' class in Bach, the educational aspect of this particular festival.
At the end of each Cantata, humorously, the chorus, orchestra, several soloists--and up to eight conductors--simultaneously came on stage to take bows. I laughed each day at this slightly preposterous concert spectacle but I was very much aware of the excellence of the triple system of presentation, where practical musicians got to know Bach with unexcelled thoroughness through actual performance, while the capacity audience for once really understood what the old composer was doing in these wonderful works, so often listened to in total incomprehension. You never saw such enthusiasm! As far as I could see, every performance was sold out.
If you think audio engineers work long hours, you must understand that these musicians, the instruments, voices and conductors, had to master a complete Bach Cantata each day, rehearsing all morning and all afternoon to perform at 5:15, and in addition they somehow learned and produced a Bach Mass and a Haydn Mass for two evening performances plus the gigantic early 19th century oratorio "Elijah" by Mendelssohn lasting some 2 1/2 hours, also performed twice. They never stopped working. Rehearsals went straight on through the evenings when the main concert was some outside group or soloist; they rehearsed all Saturday morning, performed Saturday night and again Sunday. A stirring musician's "vacation" if you had the guts! That sort of work generates incredible musical enthusiasm and the excitement communicated itself to the audience day after day. Yes, live music can easily be both thrilling and exhausting.
I found the third element in that triple array the afternoon I arrived. Public Radio broadcast of most of the Festival via the U. of Oregon ("OR-gan") station KWAX-FM, something to do with a duck, the University's athletic symbol. Almost everything was taken down on tape or broadcast direct.
The Cantatas were recorded "live" and broadcast, complete with lecture, the next morning. Some of the major evening events, including ''Elijah," were aired live in real time and also recorded, later to go on National Public Radio (NPR) via satellite August 24 through 27. (If I am right, these events are taped by the local stations ad lib and appear on their schedules during the following months. Also perhaps on all sorts of exotic stations a half-world away, tapping that 22,000-mile-high radio source.
Astonishing.) It happened this way, I do, indeed, try hard to be the pure musician at live concerts and I am, as long as I keep my eyes closed. But once they open, I can't help but look around and, after considerable practice, I begin to notice things. At the very first Cantata my wandering attention was immediately caught by something odd up front in Beall Hall (" Bell"), where most of the musical events occurred. On stage were the chorus in back, the orchestra in front, and on one side a couple of solo voices.
Right off, I had noticed a standard stereo mike array, a coincident pair (AKG 414s) hanging out front of stage center. That would take in the over-all. Automatically, out of habit, I looked in back of me and discerned two pencil-like mikes hanging far in the rear of the hall. Ambience! But what of the soloists? They were much too far from the overhead stereo mikes, yet there appeared to be no solo mikes at all. This was odd. I began to get interested in spite of myself.
Then I saw, down below them and set on the floor in front of the stage, what seemed, for the moment, to be two music stands, angled diagonally upwards at the level of the singers' ankles. Cue sheets? Music desks for far-sighted singers? What WERE those things? Crazy, because they were made of clear plastic, a pair of desk-like pieces maybe three feet by two and a half. And then I saw that there was nothing on them at all.
Nothing except a small dark metal square at the center of each and wires.
Wow--my inner light bulb flashed.
PZM microphones! Hand mounted in Plexiglas. It had to be them. Nothing else made sense. I was so excited that I began to mutter to my hostess in the next seat and was rewarded with a shhh--where were my concert manners? Then, almost forgetting poor Bach, I discovered more. In front of the squarely modern pipes of a "Baroque" organ at the rear of the stage, high in the air, I began to discern two more vague little metal squares, seemingly floating in space.
Very odd! Then a faint pair of lines manifested themselves--the almost invisible edges of two larger Plexiglas plates in which the metal squares were centered. Plexiglas is an incredibly transparent material! The organ pipes showed right through those squares without a trace of distortion, as though they weren't there. It was impossible to make out all four sides at once and the faint trace of a piano-wire guy that tied the two plates together and (mostly) motionless.
So, back to Bach, and I had to keep the big secret to myself. For days. I just let things happen, and went to more concerts. (But I listened to the morning Cantata broadcasts with avid interest, you may be sure.) Then towards the end of the Festival there was a grand reception for the Visiting Music Critic, Harold Schonberg of The New York Times, who happened to be an old-time friend of mine from years back. He gave two lectures, old singers and old pianists (recorded), and we spent a couple of informal evenings at my hostess' house before I was to "meet" him at the big reception. Ha! Mr.
S. was the visiting lion that day but the person I instantly noticed was a young man with a large KWAX button on his lapel. My moment had duly arrived.
WERE those PZM mikes? Yes! And to whom should I talk about them? Alan Yordy, he's your man, the Operations Director of KWAX and that's him, right over there on the couch.
Alan Yordy turned out to be a longtime reader of this mag and of my department, so in moments we were deep into PZMs from the inside out, as of what could be one of the earliest true-classical pickups with this remarkable new species of mike, worked out and operated by Yordy himself. That meeting was followed the next day (between rehearsals and broadcasts) by an on-the spot tour of the Beall Hall set-up and a long discussion which took both of us through our lunch time. Worth starving for.
At this point I'd better pause for station identification. What IS a PZM? Though PZMs are already several years old, not everyone has found out about them.
The pressure recording theory behind the PZM was developed by that versatile engineer Ed Long and his associate Ron Wickersham, and prototype mikes came from Ken Wahrenbock in 1978--that recently. A batch of working capsules, mainly for further development, I gather, were emanated by Syn-Aud-Con before Crown took over the whole idea commercially a year or so back. Crown already has two production models available and two more coming. The PZM is fundamentally unlike any mike before used. Not the capsule itself, though it is tiny enough to go inside a phono cartridge. It's the placing, in a curious acoustic zone just above a flat plane where direct and reflected sounds are totally coherent within the audible range, minus cancellations or colorings of any sort. Stick your picking-up unit right there, your sound is extraordinarily clear and "flat," minus directionality, and the mike shows unusual properties never before observed. I was briefly reminded of "floor bounce" mike placement, but the PZM distance from the primary flat plane, floor or otherwise, is on the order of four thousandths of an inch. Extraordinary! Down in that micro-sonic (non-TM) world, impinging sound on the tiny capsule is to ordinary sound as laser light is to ordinary light. Well, not exactly .. . but anyhow, something altogether new in audio. Totally coherent, precisely the original acoustic "signal." No internal mike coloration in theory.
The PZM uses a tiny cartridge or capsule, mounted against a flat plate which may be--must be--extended by larger plane surfaces, anything from clear Plexiglas to a piano lid, if you are to reproduce adequate bass. (Here there is a definite relationship to the old flat speaker baffle--the larger the area of the plane, the lower the bass pickup.) The two Crown PZMs come ready assembled on two sizes of metal square; Alan Yordy's PZMs in Plexiglas were handmade, out of the capsules that were sold separately by, I think, Syn-AudCon. To an extent, Yordy had to make do with what was available; his 3/16-inch plastic sheets were not as thick or as big as he would have liked--optimum would be four by four feet and a quarter inch thickness for stability. But for voice pickup, chorus or soloist, the slightly smaller rectangles were OK. I got a good close-up look at them and must report that they were elegantly put together and machined, without so much as a scratch or even a smudge on the plastic. Far clearer than even plate window glass! So if you think that these big flat plates are going to be clumsy to use, keep in mind that in practice (and with care) they are virtually invisible to an audience. And they can be set up in unusual and even bizarre ways, such as an ankle-level diagonal aiming from down below used by Alan Yordy for his Bach solo voices.
Note that the PZM coverage is, as you might guess, hemispherical, and in theory the response is absolutely flat and unchanging right out to the edge of that hemisphere. Thus movement of the sound source through the mike's pickup range does not result in the changes in sound that occur with virtually all other microphones. Also, the PZM has extraordinary "reach." It can detect intelligible whispers at astonishing distances and the same with musical details-a shotgun mike but with total clarity and broad semi-omni range. Finally, the PZM won't blast, even inside a bass drum. It'll take 150 dB but maybe not an "1812" cannon at two feet, in case you wanted to try. More on Bach and Yordy next month.
by Edward Tatnall Canby (adapted from Audio magazine, Oct. 1981)
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