Adventures in Surround Sound, from 7.2 to Quad 
(personal and historical notes, basics, and acoustic realities often forgotten)
= P a r t  3 =

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Jousting at Windmills
An "Infamous" Whistle-blowing Letter to Billboard

Looking back on episodes like what follows from today, I wonder what ever possessed me. I must have been HATED for a few of the things I did in good conscience, like this whistle-blowing. Certainly you realize why Don Quixote is a poor role-model. Try to tell that to a young, alert person who's out to: "save truth, justice and the American Way..." Phooey. BTW, Since Surround Sound 5.1 is really just Quadraphony with an added front center speaker and a distinct sub woofer channel, the experiences with quad are completely applicable to the latest surround sound systems. Suddenly 30 year old events are important and fresh all over again, and what follows is not so much quaint "history" as it is "background reading."

As luck would have it, I was signed to an exclusive contract with CBS Records (long before Sony took it over), when the first Quadraphonic craze hit. There was a close connection between CBS and Sony even back then, and Sony had (through a long, devious route) become interested in a surround system which CBS Laboratories in Stanford CT had fooled around with in the late 60's, abandoning it eventually. This was an interim, shortcut method to fit (encode) four channel audio masters onto an ordinary two-track record, then reconstruct the four (decode) on playback. Ben Bauer, an extremely talented engineer and delightful person, had led his CBS team through various alternatives in the late 60's, only to decide none of them really worked. He recommended that the company wait for a genuine four channel home delivery system to evolve, that this wasn't it.
Poor Ben was surprised a year or two later to get a call from an executive over at "Black Rock", the CBS headquarters in NYC, asking about "this new four channel sound stuff." The executive had just been grilled by some of his contacts in Japan, who had found this abandoned "matrix quad system" (as it was called), and thought it looked like an easy way to expand sales. They wanted the USA offices at CBS to assemble some prototype recordings that used the system, and would in return send the NYC offices some tests they had been trying out in Japan. There was a buzz-on, and Ben was asked to comply. He had already proven that all such bootstrap methods, trying to get something for nothing, were doomed to failure. But now he was going to be required to do it anyway, or at least invent a few tricks that would satisfy the home office, and which they could send to the Japan CBS offices. He hoped it would then all fade away with that.
We got called into the fray soon enough. Here we had one of the hottest classical albums ever made, and it seemed a natural for a new quadraphonic version. Rachel Elkind took a couple of long calls from the heads at Masterworks division (no doubt John McClure, perhaps also Tom Frost and Clive Davis), and suddenly we were in trouble, too. I'd been making four channel surround masters for a dozen years by then, and knew a little about surround sound. We'd been the news bytes about several of the majors, as they began pioneering this newest home audio idea. We learned that JVC in Japan had been developing a clever idea that actually *could* squeeze all the necessary information into a conventional LP -- four discrete channels.
JVC Japan was pushing forward with their CD-4, an honest, if complex quad method which was loosely based on Jerry Minter's early Stereophonic LP's (two track stereo) of 1958: place the extra information as a super high frequency tone that is FM modulated, more like radio than stylus in groove records. Minter had taken the (mono) "sum" mix of Left and Right, L+R, as it was called, and recorded that in the usual way. He took another mix, a "difference" of the two sides, L-R ( which means the R was phase-flipped 180 degrees and added to normal L), and modulated a 25 kHz tone with it, yielding the radio-like signal. That was mixed with the mono sum to make the record. Since 25 k is above most human hearing, you couldn't hear this tone. But an ingenious, inexpensive add-on circuit picked it up, detected it, and mixed it back in a simple circuit (called a "matrix") to obtain the original two tracks, L and R. Mono listeners just heard the mono mix (so it was compatible). Clever idea. Anyway, JVC was doing this stunt twice on a stereo LP, getting four distinct tracks from it.
The good idea was never trouble-free. Early on we were given some of their special equipment and cut some albums using the cutting facilities they'd set up in the USA. (It was amusing how several CD-4 doors opened after the letter below was published... ;^) The JVC method was generally a bit noisy, prone to distortion, and was delicate to install and operate. But it often sounded quite good, too, when treated with some TLC. Sony had tried and given up on such a high-strung design. Can't say I blame them, it was a major engineering campaign for JVC, and for RCA, their US affiliate on the new "QuadraDisks." Sony/CBS instead continued with their blood-from-a-stone pseudo-quad designs, much as Sansui, yet another Japanese company, was doing at the time with QS. Ben Bauer came up with one of the best choices of a poor lot, and SQ was born.
A hasty appointment was made, and Ben came to our studio downstairs in the brownstone one afternoon in the Summer of 72, with a bright, sharp engineer named Dan Gravereaux. They brought with them the latest "encoding" and "decoding" equipment they had thus far produced. We were given some copies of the very first titles that CBS would be putting out in the new scheme, and photocopies of a few detailed technical articles which described the methods and history behind SQ. Their "job" obviously, was to convince us to go along with their scheme. The background scuttlebutt I've related above was only learned a couple of years later. I felt bad for Ben, who was obviously such a nice, urbane man, with great charm and knowledge.
But I also felt bad for us. We spent the next several weeks trying to get what we could from the SQ hardware. It was pretty gruesome. I guess for many producers and engineers SQ was adequate. It could handle a kind of ping-ping pong-pong stereo, as I called it, as long as you simply pan-potted a few locations around the periphery. It was impossible to have natural or simulated instrument leakage: the same sound heard over more than one or two channels. A ghost center effect, something I'd used for years, was out of the question. It would gather up on the final Left track, and cancel out on the final Right track. Other combinations, like diagonal splits, were even worse. Baloney!
A Saber-cut to the Heart of the Matter

Out of curiosity and pique, I came up with an amusing, barbed demonstration track in quad that made our point with a razor-sharp sabre. The track sounded like a few minutes of a large group of people at a cocktail party, yatta-yatta-ing away all around the room, recorded cleanly in discrete quadraphony, hard to follow any one conversation. BUT -- when this clever little "nasty" was fed into the SQ encoder something strange happened: nearly all of the voices slowly faded away into a soft background sputtering, leaving but one voice that could be heard! And that was the voice of our good friend, Bob Schwarz. He cheerfully deadpanned, in his wonderfully rich radio announcer's voice: "Hi, are you enjoying the party? Me, too. But where did everyone go? That's odd, I couldn't hear myself there in the discrete. But now I can on the matrix. There must be something funny going on with these matrix systems, don't you think?" Then everyone else's chatter faded back in. Deathless silence from the CBS people we played it for. Priceless moment. (Also stupidly naive and showoff-y, not something that would ever be mentioned in a good class on Diplomacy... ;^)
Sansui QS had the same Achilles Heel, also the older pioneering RM. All of the Matrix-Quad systems do, for they all toss away half of the information. It's referred to in the original 1972 letter below.

We knew CBS's company plan, and we had just mixed our S-OB multitrack tapes once again to real surround, before getting the new equipment. There were a great many "tricks" we would have to use to cover my "impertinent questions," to continue doing nothing more demanding than what I'd already been doing for years. These tricks were conscious, deliberate clever workarounds, and you really had to think twice at every step about what you were doing, and what would get translated reasonably well, and what wouldn't. Or just try to be satisfied with the old Double-Ping-Pong, as we'll describe next. This is not the place to go into these additional SQ-encoding kludges. I'll post some of the details eventually, some scans of my notes and diagrams that were necessary if you were to avoid getting bitten by the severe creative and musical compromises that SQ would require. (Note: the first few diagrams are already uploaded and ready to peruse on the next surround page.)
I found Sansui's QS scheme somewhat more to my liking. It suffered somewhat in front separation compared to the CBS, but when the two-track versions encoded by Sansui's QS system were played back on ordinary stereo equipment the results were very close to the way Rachel and I had been making two track stereo masters from all our four track masters for a few years. CBS's SQ design was just plain "weird" when heard on normal stereo, except if you restricted the placements to normal two tracks up in front, like close mikes over a band or orchestra, while the "rear" channels were distant reverb hall-sound channels. For that it was fine. Also Enoch-Light variations on unsubtle ping-ping pong-pong mixes worked well, especially on the latest "Logic" decoders, which rode gain automatically, trying to enhance the miserable separation of all matrix designs. Light would place antiphonal instruments only in the exact four channels, not much in-between, and that kind of limited quad was reasonably well served by the matrix systems with logic steering.
CBS had no sooner put out our "Switched-On Bach" in an SQ edition, that we were able to hear it on their best decoder. The result was depressing, very much a warped joke version of what we'd made. Well, it was on all but one track: the Two-part Invention in F. That one worked quite well. Why? Because it had come from the only mono master on S-OB, the first track recorded (I had "stereoized it for the first stereo release). So we were forced to use pan-pots to walk and jump the mono Invention all around the room, to the exact four speakers, not much in between. It's effective in small doses, I guess (the Invention is short), and quite a few people wrote rave reviews about the SQ version. I wanted nothing more to do with it. CBS refused to use the "competition's system", the JVC QuadraDisk, which had been improving steadily. I was signed to the wrong company! (On the other hand, to be perfectly fair, the JVC system had great trouble handling many high frequency sounds on Sonic Seasonings and some of our other masters without audible distortion. We cut a few careful tests on CD-4 and had to throw in the towel -- our music was just too demanding -- ouch! You'll detect that we'd decided to wait it out by the second letter below. And, well like, it's only taken a quarter century! ;o)

If we'd signed with RCA initially, as we nearly did, things would have worked out differently. We'd have put out many of our albums in genuine quad (discrete, meaning honest four ins and four outs), and neither of these letters would have been written. Then it would have been upsetting when CD's first were introdiced an absolutely NO ONE took advantage of the four channel format they offer (still do). Yep, a plain old CD can store about half stereo's maximum time, or 38 minutes of pure quad! Bet you didn't know that before -- it's never been implemented on CD-players or in the studio, to the best of my knowledge! Stuck between greed or honesty, we took the path that many (most?) artists probably would not: we cut off extra royalties from sales of SQ versions, and demanded our pseud-quad S-OB be withdrawn! This was a big financial sacrifice for us, just a small studio with not many artists, but it was the only ethical thing we could do.
There might be poor souls out there who would think the mild chewing up of S-OB by SQ was "the way it was supposed to sound." We wanted no part of deceiving the loyal fans we depend upon. I did the same sort of thing when the early "copy protection" schemes for digital (ca. 1986) appeared. They wanted to slip a deep notch filter into all CD's, with nasty results to the music (a few high piano notes would nearly disappear, fer pete's sake!). I was depressed by how few other artists signed the protest petition circulated widely at the time through the major recording organizations. Is greed just "the Amuhrican Way?" (Have mentioned this before, on the Disknotes page.)
Anyway, in 1972 I wrote off an infuriated letter, reprinted below, warts and all. (Lordy, the execs at CBS and long suffering Ben must have been apoplectic about it!) Billboard magazine had been running an excellent coverage of the ongoing "matrix vs. discrete" debates, so off to them went this "letter to the editor." Don't know what their editor made of it, but he printed it, one of the longest they've ever published, a full page. I've been told it created quite a "tempest in a teapot," and helped damp a bit of the Wave of BS that flowed out of the matrix fiasco. I hope so, I really do hope so...

(Top of the Page)
Moog Soundings
(the title the editor came up with for my letter...)

Dear Sir,

Thank you for your particularly comprehensive and clearly unbiased reporting especially with regards to quadraphonic sound. As one person involved in quadraphonic sound ever since the technology became practical, I have been excited to see the general interest now rapidly growing in this method of "super stereo." But no one in our industry can be anything but apprehensive if not confused about the many contradictions, ridiculous claims, putdowns and hysterical confounding of facts that has made mockery of all the recent quadraphonic meetings, public exhibitions, publicity and press conferences.

The crux of all confusion seems best indicated by the so-called "Great Matrix Debate." Most of the reports you have presented over the past year or more have centered on that kind of "my system's better than yours" game. Well and good. The business and creative elements of the industry are perhaps Billboard Magazine's primary concern. And this group has a right and a need to be told about the technology available, in not overly technical a manner.

It is no secret that we all stand to gain a great deal once successful quadraphonic hardware becomes standardized. But nowhere has anyone really attempted to state a few simple generalities which, like it or not, ought govern our choice. Make no mistake, the choice for quadraphonic systems is ours not the technical developers and laboratories currently engaged in this sort of research. Whatever we, in fact, adopt to promote, build home units for, use to produce our records, our tapes, our artistic sound paintings i.e., the "software" of quadraphonic will become the system. All other systems will then phase out, deservedly or not.


If we may look back to the similar birth of stereo in 1958, it was the few bold pioneers: record companies, producers, and phono cartridge manufacturers, who literally forced the standardization of the Westrex 45/45 stereo-disk system. Otherwise we would still be debating the theoretical impossibility of this system, and, as some now joke back to mono--we would still be a non-stereo industry, likely much smaller than now (thanks to the stereo revolution).

If I may be permitted an opinion, the only present need we have is as that 1958 period, a workable system. As long as it possesses no unnecessary theoretical limitations, but only has a few "bugs" (perhaps lower level, slightly less playing time, and the like), we ought adopt it as we did in 1958. A few years will iron out those bugs, again as we discovered with stereo.

Unfortunately, most quadraphonic pioneers today are not willing to accept this small price for a very healthy future. They believe, many quite sincerely, that we can "boot-strap" ourselves into instant quadraphonic. Humbug!

When Rachel Elkind and I began our new "Sonic Seasonings" album, we planned for quadraphonic and recorded all the materials in quadraphonic. That master, like "Clockwork Orange" and most of our other product, is already mixed in four channel surround. We tried to process this master on all the known matrix systems, and a few not so known. I am most unhappy to report that the results were catastrophic most of the time, and ho-hum for the rest. And this was using the latest state-of-the-art matrix equipment, a magnitude better than home matrix equipment. Our "Switched-On Bach" was released in the best of the matrix systems, CBS's SQ, and we later discovered that, despite some critical acclaim, it is a pale mirror of the quadraphonic master. Worse, the musical balances are irrevocably bastardized so that, at many times, solo lines are obliterated by accompaniment.

Columbia has generously agreed to withdraw this album. If you should come across any remaining copies of the SQ version, avoid it like the plague! -- a strange sentiment for profit consciousness, but in the long run we believe it is the only valid decision possible. (Please note, re: the recent plea for compatible discrete/matrix disks, they would be exactly as inferior on all non-discrete equipment. Let's not allow ourselves to be conned by glib claims to the contrary for this ridiculous comprise). No other TEMPI product will be marketed in quadraphonic now for a while until a non-matrix system is accepted as an industry standard. Perhaps the JVC/RCA carrier disk is the answer. It is a "workable system" at least.


Admittedly some product on matrix disks sounds perfectly fine. Indeed, a master remixed for a "ping- ping-pong-pong" quadraphonic will, in general, produce acceptable results on most of these systems (which despite mathematical differences tend to sound very alike). The strong loss of separation and phasing alterations/ interactions of all these systems is universally acknowledged. One reads with disbelief in your pages the number of people who rationalize such alterations as desirable. The dilutions do make a ping-ping-pong-pong master sound more diffuse and less gimmickry than the same would sound in pure quad. This latter we now find termed "discrete."

For "discrete" product to sound natural and acceptable to most people, we will all have to learn as we did in stereo, to produce master 4-track tapes with ambience, cross-relations and shifting phases of all kinds. There are, unlike successful matrix masters, many families of mixes possible which will attract even the most naive consumer, who, let's admit, has been less than excited by any of the matrix systems. Oddly enough, the ingenious matrix systems could play an important role in allowing producers to mix discrete masters with far more directionalities than the ordinary recording studio quadraphonic console permits. We can all profit in the end.


So I come across as another one of those mad discrete thickheads. I'm sorry, let's look at the reasons. You need not agree with me in a decision to wait for discrete and may prefer to go with a stop-gap measure of matrix quad. Again, well and good. Pragmatically you are probably safe. But, people, let's not "cut off our noses to..."

1) The theoretical maximum separation for a symmetrical matrix system is 4.8 dB; none attain it. Most barely attain a 3 dB. If we wish to, we can trade-off left-to-right separation for front-to-back or vice versa, as several systems do. But after all the effort the industry has expended for the 25-35 dB separation of stereo, how can we now rationalize being forever happy with 3-5 dB?

2. A two channel stereo system with about 4.5 dB separation is scarcely different-sounding from mono on two loudspeakers--unless the listener is in the exact center (as on earphones). Then the stereo effect is just noticeable. Don't take my word, try it next time you are in a studio. Have the engineer set up a cross-mix of a stereo master, any master, to give 4.5 dB separation. Then move about a little and listen. Compare it to a mono tape on the two speakers.

3) Matrix (forgetting the mathematical type) means "system of intermixes." Three signals can be mixed in several ways to give three new signals. These new signals can then be re-intermixed to produce the original three unless we throw out one or more. The 4-2-4 matrix for quadraphonic discards half of the new signals. No decoder is possible in this case. That's a misnomer. Re-encoder would be the correct terminology.

4) Most consumers at home would object to listening to records from one fixed spot, and no one else in the room would occupy it at the same time anyway.... a shift of a few feet causes a measurable change of loudness of sounds from a loudspeaker. For quadraphonic, the balance shifts more than the available matrix separation, i.e., despite smokescreen claims to the contrary, even an educated ear could not tell matrix quadraphonic from mono over four speakers with minor exceptions, except from the center of the room. N.B. with well mixed discrete just about anywhere in the room is usable.

5) In a few systems, like the basic SQ, the left-to-right separation is strongly favored, while front-to-back deteriorates to an essentially inaudible amount. These systems cannot be differentiated from stereo over four speakers except from the center of the room, again with minor exceptions.

6) Clearly, unless we are willing to depend on the ignorance of the consumer, which is indeed a sad fact, some enhancing logic is absolutely essential for matrix systems. Thanks to the kind help of CBS Laboratories, we at TEMPI were given a long opportunity to hear and work with the latest Logic-SQ equipment. Compared to all other systems, including SQ without logic, it is the only system which even begins to sound like a quadraphonic master, for some material. Our "Switched-on Bach" SQ disk still was awful this on equipment far superior to all available home systems.

7) We investigated the cause of the mysterious missing parts for "S-OB." It turns out, and this has never been in print before, that every matrix quad system has an infinite number of signal combinations which cancel out when the matrix master is encoded, and can never again be recovered.

8) To prove this important point, we produced several quadraphonic mixes which vanished when encoded, leaving only a very soft sputtering! The SQ was by far the most tricky matrix to find such complete examples for, but it too, succumbed. Imagine never knowing just what part of a meticulous mix will be lopped off, or severely attenuated, by the time it gets to disk. This seems eminently more important than any position- shifts that may occur.

9) If one is cautious, he can avoid these troublesome combinations. We already know that pan-pot and ping- pong-ping-pong are safe, if artistically limiting. But they do work on sophisticated systems, such as SQ with logic. Other systems are less fussy, but sound so like mono in the end that you might well ask: "is this trip really necessary?" and would you mind giving up 80 percent of possible quadraphonic effects permanently?

10) A highly sophisticated logic is already on the drawing board stage at CBS Labs and others. By breaking up the sound into say, octaves, and using logic on each band separately (not unlike Dolby-A in concept and certainly cost) a result indistinguishable from discrete quad 95 percent of the time is theoretically possible. Of course, a critical listener may still be annoyed by the "pumping" effect inevitable on gain riding devices as logic requires.

11) The previously mentioned cancellations during making the matrix record cannot be removed, how ever. Progress in quadraphonic recording and mixing will be severely limited. I, for one, would prefer not to have to carry a calculator and vector scope, or an encoder / decoder pair around with me, to cheek out feasible projects (and also worry about additional cancellations in mono playback). The quadraphonic masters for "S-OB" and "Sonic Seasonings," "Clockwork Orange," etc., do not encode properly because we refused to limit ourselves in these ways. The phase and amplitude shifts that make sophisticated quadraphonic possible here work to confuse and disable encoding. And what you can't encode never gets to disk so the new logic systems are no help.

12) Finally, these logic schemes, clever as they are, become, in fact, more complicated and expensive than the carrier system decoders so put-down with heated prejudice by the many individuals Billboard has faithfully reported on. Without committing myself to the obvious front-runner of carrier systems, JVC/ RCA, may I add:

a) The complaints of new cartridges necessary, less playing time, lower signal level, etc., are so similar to 1958's anti-Westrex propagandizement that one wonders what the commotion is all about. A lot of current high-quality stereo cartridges work fine, and that's more than the mono cartridges of 1958 could do for stereo. Ironically, lower signal levels are also heard on most matrix disks, due to asymmetrical level peaks from the matrix (which cannot be inconspicuously limited during cutting) so the overall level cut is reduced. In 1958, the same complaint was made about stereo, don't forget.

b) CBS Labs originally developed a carrier disk. It was aborted temporarily due to the limitations of available plastics and other reasons. The newest record materials already are not affected by even fairly abusive playing on cheap phonographs. A carrier system then is possible. Dirt, not wear, may cause trouble. If you think you've worn out the carrier, just reach for the record cleaner! In any ease, again this is all old crying a la 1958, and the situation is nowhere near as bleak as Westrex 45/45 seemed. Then there's still the option of converting the Teldec video disk to a quadraphonic disk of four or more hours per side!

e) Actually, even the carrier systems are "matrix" systems. The two left channels are mixed, ditto for the right. But two other mixes are made for the carriers to hold. In not discarding two of the four new signals carrier disks gain their superiority. Since no information is lost, the cancellations mentioned earlier do not occur and one can record with freedom.

d) Some have apparently heard discrete product of poorly mixed masters. May I point out that the gimmicky quad pinging and ponging is no more inherent than it was in early stereo days. And the "blend" control of those days was quickly abandoned as more sophisticated records were made. Is that not analogous to the present cry that "matrix is more natural?" It's a great big BLEND switch! Still, there is a place for blending in quadraphonic, and if a producer finds a particular matrix quad system provides a pleasing "surround" on say, the string tracks, I see no reason why s/he ought not use it. And a different system might be used for the echo signals, while the rhythm and vocal might be the best pinpointed in direct non matrix form. With a discrete release available we can have the best of all worlds! Any matrix blending will be done in the recording studio, under artistic control of the artists, producers and engineers. But a permanent blend of all signals indiscriminately at home? I don't think we'll need it and certainly not want it in a couple of years. Until then, caveat emptor!

W. Carlos
New York City

== August 5, 1972; Billboard Magazine, Page 6 ==

(Note: In the same issue of Billboard magazine,
Brad Miller, of the
Mystic Moods Orchestra,
placed a five-inch tall ad drawing reader's attention
to the above letter, with big letters:


(Brad had been another surround sound enthusiast and pioneer.
He also championed a very reasonable system of Quadracasting
four discrete channels over an ordinary FM transmitter. The FCC
hemmed and hawed, and Quad faded away. It could have all come to
fruition a quarter of a century ago! Perhaps now 5.1 will carry on.
Thank you, dear Brad, wherever you are, for
your constant support and understanding...

(Top of the Page)

In May of 1974 there had been some change of the status of Quadraphony, which was still very much in the news of industry record and engineering magazines and the like, if not in the perceptions of the public. I tried to summarize the situation in a much shorter new letter, again to Billboard. I don't remember if this one was also printed by them, as I found only a Xerox copy of a typed manuscript in my files. We clearly had made the copy and then sent the original off to them. It's quite possible that by then the initial interest had waned, and the letter was never published before this web page.
It still contains some anger, and youthful hubris but not so much as the first one. You'll see that by now I'd done my homework, and could toss-off a better grab-bag of terms, exact specifications, and evidence. It amused me, when I just found the photocopy in a dusty old file folder, to discover that way back then I was pushing for the same kind of configuration that I had just documented on the earlier pages. Can't say I'm not consistent. (You'll also notice that I end with an irrelevant "dig" about the way surround multi channels are often labeled. On my old console A-B-C and D correspond to the far left sweeping through far right outputs, nice and symmetrical. Some of the setups I've seen are Byzantine, like the way it's done for DTS masters, say wha...?) Of course the whole surround sound vehicle never completely got off the ground before now. So these issues have become timely again in 2001, some 27-28 years later! (The more things change, the more...) For historical sake, I'll include the second Billboard letter below.

More Switched-On Quad

Dear Sir,

Back in mid 1972 you graciously allowed me publication of a rather lengthy letter about the then state-of-the-art of quad sound. This continuation of that filibuster will be briefer, but a lot has happened in the meantime which ought be said. since we have yet to come up with a standardized name like: Stereophonic, or Monophonic, and although I personally prefer: Quadraphonic to the others, Quadrasonic, Quadriphonic, Quadrasound, Tetraphony, etc., let's for now simply call it by the informal: "Quad."
Frankly, I think all of us in our industry really do deserve some sort of recognition for sobriety or altruism. By 1972 and into 1873 there was still a lot of hyped advertising with exorbitant, exaggerated, confusing, and often untrue claims made about one particular system over all others. There is still some of this nonsense going on, but by and large the various manufacturers and sellers of quad hardware and software have mellowed into more refined, objective ideas in their promotions. The truths about this marvelous new medium are at last being heard. Integrity has won out, while behind the scenes, a great deal of research and development is producing valid breakthroughs now reaching the marketplace.

The Situation in 1972

Two years ago there were several Quad methods under discussion, and at that time none of these systems was really very good. In comparisons of identical recordings we made, under carefully controlled conditions and double-blind, both electronic and acoustic music, we heard how the various systems altered and corrupted our masters. It was like: SQ versus Switched-On Bach. Some comparisons:
RM Matrix: produced very decent Stereo playback, indistinguishable from stereo Quad playback, and occasionally lousy Mono playback. Much information was lost during encoding.
RM Vario-Matrix: occasionally was fine for its intended quasi-quad, but ambience and balances were poor, and much information was lost.
SQ Matrix: produced mediocre Stereo playback, (with both rear channels "folded-in" to equally ambiguous center-fit 1) , indistinguishable from-stereo Quad Play and usually lousy Mono Play, and much information was lost.

SQ Logic: occasionally was fine for its intended Simulated Quad Play, but ambience and balances were poor, the first logics were slow-acting and "pumped" (newer are much better), but again much information was lost.

CD-4: produced very decent Stereo and Mono Plays, but quite noisy and often distorted Quad Play, which frequently had a muffled quality, although no actual information was lost.

In general, all other matrix schemes were even worse than RM (Sansui originally called it QS) or SQ in most respects' and CD-4 was the only available non-matrix schemes. All the quad disks had somewhat lower levels than standard Stereo discs. The CD-4 at that time had theoretical reasons for the reduced level, and both SQ and RM have frequent out-of-phase peaks (rather higher than normal stereo) which require a more cautious cutting level. Audibly, despite what the V.U. meters might have said, they all sounded softer than Stereo, in any event (with a few rare exceptions):

So, at that time, I felt the safest decision was to develop a "super-stereo" mix-down from our quad masters, and sit out and wait until videodisk technology suitably modified, or CD-4 type records yielded results which could be called 'high- fidelity" as well as Quad. Also, since the matrix theory as a whole permanently discards one-half of the Quad material, I believe it is actually Pseudo-Quad. Perhaps "discrete" quad was originally a term dreamed up to hide the fact that "discrete" is really the only genuine Quad. I second the suggestion that we rename discrete: "true Quad", and matrix: "Simulated Quad", not unlike the old ruling about mono masters "rechanneled for stereo".

The Present (New Developments)

But now it is 1974 and the situation has changed A few "Simulated Quad" methods, notably SQ, have developed special mixing console adapters/ rechannelers which prevent any mixing combination which would cancel out (partially or wholly) -in matrix-encoding from ever being produced. The producer and engineer can call for all the usual positionings, echo returns, and the hike' but only the SQ-safe ones will go through "directly". The others will in fact be altered from the intended positions, and added along into the mix with no level drop. The matrix-limitations are still there, perpetual motion still doesn't exist, but at Least you no longer need worry about that. Simultaneously a "true Quad" master can be made on a four track recorder, for Q8 cartridges, CD-4 disks, or any other discrete release now or in the future. All in all, it's a most commendable effort, especially for simplified and non-critical applications.

Much more exciting is the discovery that the one preexisting "true Quad" method, CD-4, has not been sitting idly by. Since in theory this remains a
workable system, it was "only" a matter of time & dedication, genius, money and effort before really High Fidelity Quad records (and we all want those) could be cut. The surprise for us all is that these goals have recently been attained. Although CD-4 presently remains a delicate affair, with top-quality equipment and critical adjustments required at ale points in the chain, it works very well under good conditions.

In March Rachel Elkind, my partner, paid a visit to Tom Nishida at the west coast "JVC Cutting Center". She brought along a new quad master she had produced recently, and I engineered of a very demanding piece of music by Eric Siday. He utilizes traditional and electronic sources together for genuinely exciting results that would place severe demands on any system. In our A/B comparison of the test disk Mr. Nishida cut for Rachel, it was next-to-impossible for us to be certain which we were listening to: master or disk. Only the presence of slight surface noises and a couple of clipped peaks gave any indication. At last even Eric was convinced. And he had found the A/B comparisons with the leading matrix system dismally easy to differentiate, so unfaithful was it.

We also have learned that CBS has taken delivery of CD-4 equipment. Quietly, this giant too, is experimenting with perfecting a high fidelity "true quad" record, as are many other companies. With the newest modifications (several major; a few minor but with great improvements, such as new cutting stylus shapes) it is at least conceivable that records worthy of the small but not unimpressive audiophile quad market could be in stores by Christmas. The not so critical lower-priced phonograph users would still be best served by that new SQ-mixdown type Pseudo-Quad record, at least until less delicate and expensive Hi-Fi "true quad" hardware is developed.

But don't throw away your old matrix encoders yet - or ever! As I mentioned in my last letter, these devices borrow two fantastic concepts developed back in the late 50's by pioneer Ben Bauer: 90° phase shifters and matrices. And those concepts, if used in unorthodox groupings, will be significantly important for those of us who wish to push open the limits on our new generation of 'True Quad. In a very real sense we all are the winners after only a few short years now passed.

Speaker Placement as a Limitation

With the dawn of "true Quad" presently before us it might be appropriate to suggest one more relevant observation. From 1961 to 65 I was involved with a small group of experimenters working with the then unnamed and primitive four channel techniques out of which our present "Quad" developed. We must have tried just about every conceivable microphone and loudspeaker placement during those years. It ;s ironic to look back now and realize that one of the first tried and least successful was our dear friend. one speaker in each corner -- 360 degree surround-sound. It would be out of place to get into a technical discussion as to why this idea which really sounds "obvious" and "natural" was not so optimum for human-style two ear listening. What is important is that there are a great many placements which give the aural illusion of 360 degree sound, and most of these do not have speakers physically behind the listener'

Actually, those who have lived with quad speakers in each corner now must realize that it gives us four of those old stereo bugaboos. "hole-in-the-middle". Instruments and voices simply refuse to blend with 90° separation between mikes and speakers (mainly the latter). I won't pretend that the final placement we preferred back in the early 60's is the ultimate answer? But many people are using it now in their homes and studios: four speakers in a deeply curved 180 arc, or 60 degrees between each -- like an old Cinerama screen! But the most fascinating thing is that it not only eliminates those four holes-in- the-middle' but, with no particularly involved mixing, it gives a completely convincing illusion of sounds Behind, To the Sides, Above, Below, Near, Far -- a solid curtain of sound!

Speaking from personal experience, Rachel and I have, in the five years of records between our "Switched-On Bach I & II" returned to this deep-curve speaker configuration. we audition all quad tapes on it, we mix to it, we use it to show off quad for our friends and business associates. Though this is a limited sample group, we have found:

Everything is easier to locate, including mistakes (which one can fix before a master leaves the studio).

2) We have been able to record a live orchestra on all four channels (not echo-only on rears) without an unnatural sense of being in the middle. The reverb seems to come from all around, even behind, however, yet the placement of each instrument or section of instruments is unbelievably well-defined in a three dimensional space unattainable with either stereo or one speaker per corner quad.

3) For less traditional records it is not difficult to give the convincing effect of instruments all around you, including dead behind and ahead, or directly at each side. All of these are exceedingly poor on the standard quad speaker configuration.

As farther evidence of 1), listen to any matrix quad, especially one that uses logic, using the 180 degree arc of monitors. The old limitations, pumping, instabilities, and the rest are at once exposed to the ear. In a way this improved speaker configuration really requires that truly discrete recordings be used.

Forgive the cliche: "Try it, you'll like it!" But I can't help but recommend that we begin mixing for and playing quad for our customers using this simple variation and watch us all benefit the great results. For those who are fond of naming things, we'll want to call the channels: Left Side, Left Front, Right Front, Right Side, all in a row, or as simple as A-B-C-D!

W. Carlos
New York City

== May 10, 1974; Sent to the Editor, Billboard Magazine ==
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