Adventures in Surround Sound, from 7.2 to Quad 
(personal and historical notes, basics, and acoustic realities often forgotten)
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Digression III -- Other Surround Options
"Depth" Quad -- a good old idea

No sooner had stereo been introduced to the masses in 1958, there were fools like me thinking about the next steps. The late, great Bert Whyte (who recorded some of the finest stereo masters for Everest records, remastered now on CD) wrote a monthly column (in Radio/TV News) that praised three channel stereo. He had campaigned in 1956 for a home medium with three tracks, especially after Wilma Cozart and Bob Fine had thoughtfully arranged a secret demo for him of three-track orchestra recordings they were making for Mercury Records. Those first mentions on stereo in Bert's "Certified Record Review" had electrified me, and began my path that led to my first Switched-On recordings. But four-track equipment came about more easily than three (just double up two quarter-tracks as I did on my little custom Viking deck). The question arose: "where do you put the extra channels?
Above is one rather fascinating idea I read about and tried with that Viking recorder pictured way above. The microphones are positioned in front of the sound sources in a similar diamond shaped pattern. The left and right channels are moved wider apart than you'd use with 2-tk stereo, and the center is filled not once but TWICE!. There's a mike that's really up close to the musicians (assume this is a music session), and another further away than the left and right pair. For playback you duplicate the positionings as you see here. If a person were to walk about while speaking, in and around the microphones, there would be an uncanny ability to judge exactly where s/he was at any moment if you listened with this "Depth" Quad arrangement. It may not work over a very wide angle, it's certainly not as "surrounding" as some of the other schemes here. But it is a charming way to duplicate a soundfield in startlingly realistic ways. Those of you who can try it out will be happily surprised at the reproduction.
Note: the close speaker would be best if mounted rather low, so the center distant track will not be blocked. The mikes don't need the same finesse. It's effective to deepen the positions even more if you have the room. I first tried it with a deeper than wide arrangement, and that was pretty cool. The mikes are just as important as the speakers, and we have another page devoted to this side of the equation. Clearly this is not the place for the way most of us work today: panning and repositioning a multitrack source in the mix. Depth Quad works best with one mike per speaker. You can try more than four channels, but of course, dovetailing the additional channels to either side of this one. How about four more, in pairs, to either side of these here, one close, one distant, total of eight -- gotta hear THAT someday!


"Diamond Surround Quad" -- a poor old idea

Here's another "diamond" arrangement for four channels: Left-Side, Center, Right-Side and Rear (similar to what's called: LCRS). Offshoots of this one have been widely popular, as it is the basis for the Dolby Stereo matrix that we've all enjoyed many times (Dolby carefully moves the sides up front). Electro-Voice was an early advocate of the above, but this was before "logic steering" circuits simulated full stereo separation. Sansui used a similar plan at the core of their decent QS quadraphonic system's "Regular Matrix." But they finally adopted the much worse "obvious quad" layout scheme, in a rush back to the corners, feh. Most of the ill-fated quadra-phonies made the same mistake, although they added logic circuits to help enhance the limited separation (nothing filled in the big "holes"). CBS/Sony had a worse scheme called "SQ", which needs a bit more space to speak about, so we'll put that tale on a related matrix-wars page HERE. There's additional tech background on matrix surround systems HERE.
Not many four channel systems stayed with this "diamond" plan. There were problems. The angle between adjacent speakers is a rather unrealistic 90 degrees. Ever hear stereo with the speakers that far apart? Yep, no "fusion" between them, a hard to ignore "hole-in-the-middle", as it's usually called. With the "Diamond Quad" scheme you get four of those black holes, four large sectors in which no sound source seems to be located. One might place "filling in" speakers with fancy logic circuits that derive the best-guess signals that would be expected when the actual channels are outputting a particular pattern. Klipsch did this with his Heresy speakers to fill the large gap in the stereophony that two corner speakers caused. We spoke about that earlier, and, yes, my center speaker is one of those Model-H for heresy designs: meant only for along-the-wall placement, and not the bass response of the bigger monsters.
But without four more speakers to try to fill in the holes (eight in all!) this idea doesn't work too well. Another problem is that when you face forward it's difficult to tell what's coming from exactly in front of you versus exactly behind you. (The most reliable way is swing yourself around sideways, then the other two channels become ambiguous -- and so forth.) You can conduct the blindfold tests I used to amuse (bore?) guests with. You need a tiny noisemaker, like the toy metal "crickets" or "clickers" that novelty shops sell. Blindfold the guest, and move the cricket all around, making the sharp click sounds from every direction you can think of. A weaker chirp right in front and below is nearly never heard as coming from there. And behind is often confused with in front. Even with discrete channels, you'll really only detect three of them at a time if you adopt the plan above, a poor old idea we can dismiss, at least in this form. (It will return with Dolby Stereo, a different story, covered below.)


dolby dia
Dolby Stereo -- Making the "diamond" work

With several modifications from the above "diamond", we obtain a much more effective plan, one that's at the heart of most motion picture stereophony, from Fantasia's Fantasound, through the early 50's CinemaScope films, and ending up with Dolby Stereo. The Left and Right channels have been moved back to the front. In this case they're rather closer together than you'd choose for music, keeping in scale with the widest screen a motion picture would be projected on in a room of these proportions. That constraint produces screen-left and screen right as the widest positions. Everything else not on the screen is suggested by a monophonic "Surround" channel, played on as many speakers as you can manage. There are designs that avoid some of the "comb-filter effect" that playback of the same signal on multi speakers will introduce, and other ways to diffuse the signal so that it becomes omniphonic, hard to locate, just a vague impression of sound from the sides and rear, without any accurate positional clues.
Dolby Stereo is not really multi-tracked. All the mix ends up on a standard stereo pair, usually called: Lt and Rt. What is to be heard from the C channel will eventually end up as an identical signal at the same phase in both Lt and Rt (the so-called "sum" signal). What is to be heard from the surround channel is mixed into Lt and Rt at the same level, but 180 degrees out of phase (the so-called "difference" signal). As long as only one or two sounds are to be located simultaneously at any given moment, a special circuit called "logic" steers what signal goes where, and reduces the crosstalk inherent in all "matrix" methods. More than two sounds at once, and you get a vague blur of sound all around. For the particular purposes of film sound, especially when the engineers have monitored through the matrix and can judge the final results, it can do a reasonable job of suggesting a real four track experience. For music it's a tradeoff, often a major one.
But the monitoring setup shown here is not designed just for listening to pseudo-surround sound. It works splendidly for discrete four channel presentations. Since the surround speakers are usually smaller and less wide-range than those in front, you must bear that in mind when recording music and sounds for playback with most systems. Usually a single subwoofer is added, and this ought improve the overall results and visceral "impact." That's why most of the setups we'll be discussing employ at last a single subwoofer. The standard philosophy is to position it anywhere practical in the room, as low bass is not too directional. Some engineers like to play pink noise over a subwoofer that's placed in the listener's position, then walk around and find a place where you hear the low rumblings best for that room. And that's where you put the subwoofer. There's more to be said about this, but let's first move over to surround schemes better suited for music.

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5.1 Surround Sound for Music
Typical Surround Monitoring Setup -- 5.1 Channels

Now this is the monitoring arrangement I hope each of you has or will have, to check out your surround mixes. Note that this time we have a single subwoofer (position not critical), as most setups are arranged that way. You lose only a little compared with stereo subwoofs, since most low bass is omnidirectional (but not all -- hard attack bass sounds do establish small directional clues...). This is a variation of our initial plan. The LF and RF speakers have been rotated slightly for less "toe-in." That's because you'll probably want to allow several people in the room to hear what's going on, and many listeners don't like to have their stereo speakers too angled in these cases. There are good arguments that suggest that more toe-in has notable benefits, but this is a topic for another discussion. Similarly, the center speaker is moved slightly closer to the listener, as it will be so in most movie theaters, home theaters, and professional studios. (Often LF, C and RF will be placed along a straight wall, hmm...) (I should note that with very short, sharp transient sounds there is a detectable change with as little a variation from equidistant spacing as six inches. But this is usually not easy to hear with normal music program, up to 2-3 feet, perhaps. Be aware that the theoretical optimum is best, but also realize that you can bend the rules slightly with little harm, most of the time.) There is equipment that can correct for such differing distances by adding a 1-4 ms. delay to the too-close speaker(s). Your preference still ought be for as close to equidistant from the listener (for all channels) as you can manage. But even without delay circuits the modest change you see above will not have a major damaging effect. Since it is also quite popular, we present here it for your consideration, along with the caveats. Next let's look at a more equivocal modification...


max rear
Maximum Side/Rear Separation Setup -- 5.2 Channels

Here you see a fairly common variation that many studios are happy with. The front speakers are as they appeared in the previous layout, less toe-in, center speaker more inline with the LF and RF speakers. I've also shown the room with stereo subwoofers, as my room has them, in the original views. But here we've made a slightly larger tradeoff. The two side speakers, LS and RS, have been moved rearwards. In this case we've not gone very far, they are both a mere 5 degrees rearwards of the position above. If you try this for yourselves I think you'll discover not much change. The side channels still sound reasonably to the sides (you're losing a little of the ability to position sounds to the exact sides -- a compromise). But you'll find that the effects that you want to locate rearwards remain rearwards a little better if you shift your head about while working. Once you stop moving either setup is fine, but when you move your chair back from the console in this new setup the side/rear sounds will stay more rearward than before, at the price of extreme side positionings.
We're splitting hairs here, I admit it. Still, you don't want to go too far with this variation. More than 10-12 degrees rearward bias on LS and RS, and you create the same old problems, losing more than you gain, don't fool yourself. Try it out in several rooms using different program material with lots of side and rear activity. (You'll also get into trouble enlarging those two 65 degree sectors any further, see the next section.) There are convincing arguments to be made that this might be a pretty decent compromise to make in many studios, and in many theaters and homes. You can be fooled by the visual impression, thinking that the first variation has only front and side loci, the second adding a little rear. Um, sorry not true. The first setup can create a completely convincing wrap-around effect, which will only vanish if someone is moving greatly, or decides to sit at a steep angle to the room, sidesaddle. Then the sound will remain confined to the one hemisphere. People sit sideways all the time with the foolish four corner positionings described above. Watch them squirm and twist about, trying to figure out: "speaker, speaker, who's got the sound?" With an arc of sound they don't do that nearly as much. And you won't want to, either.
Once you hear well-mixed music on either of these systems, you'll see why surround is as much better than stereo as stereo is better than mono (nuts, I've revealed the final conclusion on page five, you can go home now... ;^). By avoiding "wasted" channels that satisfy visual impressions, you work with the way our hearing apparatus is designed, not oblivious to it! When it comes time to fill in the room with more sounds which even a moving side-facing listener can hear as surround, it's time to take the next step, to 7.1 or 7.2 channels. Or you might add the two channels halfway in between the LS-LF pair, and the RS-RF pair. This particular expansion will stabilize the soundfield, better than any five channel system, if you must move side to side. Suddenly we're slipping along an infinite regress, because once you have seven main channels, you might want another five to produce the perfectly cylindrical field of 12 channels (but whichever way you now face, a third or more of those channels will be "wasted"). How about 12 close up channels, with 12 more further away to gain the special dimensions of "Depth" Quad, described above? And there are always ceiling speakers like Ussachevsky investigated in McMillin/Miller, and IMAX provides in their theaters. It never ends! Let's try to be happy with what we've just gained, and save the next step for the future...

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5.1 Surround Sound for Films
redu front
Filmsound: Reduced Front, Wide Rear -- 5.2 Channels

Right, for music we want a wider front image, as the 30 degree separation between LF and C and RF produces. For film work that's usually not the ideal way to go. It's just a small modification, though, to move in the LF and RF channels as shown here. This is a 25 degree version. Some theaters with smaller screens might require only 20 degrees or less. Whatever value represents the most likely way your particular audience will hear your results ought determine the way you'll want to setup your monitoring space. Right here we have an excellent compromise for both music and film mixing and monitoring, but one that favors the film soundtrack to purely musical use. It will also be practical in larger home installations, where the rear wall behind the viewing chair or sofa prevents any rear speakers anyway.
The one weakness here is the two angles of 70 degrees, LS to LF, and RS to RF. Those are about the maximum separation between any two speakers if you expect imagery from in between each pair to "fuse", and not create "holes" in the soundfield (90 degrees is certainly too wide). That's one of the reasons to prefer about 60 degrees between each channel, except the fronts, where it probably ought be somewhat smaller (remember, our most acute directional hearing is up front). It's surprising you never hear suggestions to divide the whole semicircle by five channels equally, placing the LF and RF even further apart, or about 40 to 50 degrees between each channel (no "holes" at all) as was described earlier. It would certainly work for music, whereas you'd need a 90 degree wide screen (curved?) to cover that LF-C-RF distribution! For home theaters the single subwoof version shown next may be an ideal starting place.
It need not be pointed out that we're not following any engraved set of "rules" here. You won't break any laws of any country or religion if you prefer to mix your music tracks using a narrowed front soundfield, or monitor your film mix with a front field so wide no screen this side of Cinerama and Omnimax will be capable of covering it. Some engineers have reported that they find they can hear with more accuracy when the speakers are wider than the screen, more like the suggestion above. Panned dialog and effects might not match exactly, but as these nuances have been forgotten about (dammit) for over two decades, you can ignore it, too. When mixing for films it's not often you'll encounter two subwoofer channels. The so-called "Baby-Boom" of six track (70 mm) roadshow prints of only a very few major films since the late 70's have used a pair of subwoofers. These were the former midway screen channels, LC and RC that mixers had stopped using when Dolby Stereo became the major soundtrack method. Since 70 mm had the extra tracks these often were chosen for low frequencies, only. Or the extra two channels would be used for Surround Left and Surround Right, and were then called "Split Surrounds". Most theaters, though went with the next plan.


Most Popular Surround Setup -- 5.1 Channels

Now we have again a single subwoofer, as the very name for the newest digital sound systems describe it: 5.1 channels, the .1 being taken for that channel that only covers about a tenth of the usual audio spectrum. Logically many of us have gotten used to calling the stereo subwoofer/effects channels "another .1, for a total of .2", in other words, according to the convention you've been reading on this page: 5.2. Most older theaters have not yet doubled their subwoofers, and so you'll probably want to check your mixes with the plan just above. There's still one small problem, if your goal is film mixes more than music. With music you'll often want to be able to place a few instruments into the side channels, LS and RS. Solos work very well once the speakers are not behind you. It just feels like you're up close to the stage, near the band or orchestra, a very common way to hear music.
For that reason the music monitoring setups above are best served with single side channel speakers. Since now we're discussing film soundtracks, the goal changes. And to best provide the most dramatic sound locations and movements in a movie theater you might want to do a mild version of what LCRS soundtracks did for the single "S" channel -- multiple speakers. We can add several on either side, to the rear of the main LS and RS speakers, so that we obtain this next pleasing arrangement (again, note the 70 degree weak-links, something common to most soundtrack setups):


film 5.1
Full Film Mix Surround Setup -- 5.1 Channels

Note that the LS signal is being fed also to the two or more LR Surrounds, ditto for the RS signal to the right. If you won't be playing full range, wide dynamic sounds over the LS and RS channels, all these can be smaller surround speakers as has become typical in theaters since the 70's, well, even back 20 years before that. Then you can replace the large LS and RS speakers as shown above with something that matches the other rear speakers. Your choice, and also depending on what equipment will be used in the final theaters, a best guess. Since many modern theaters have sufficiently wide range auditorium speakers to play nearly as wide ranged (dynamics and frequency response) as the screen speakers, perhaps the setup shown above will be the most useful way to hedge your bets, and not compromise what you do in the mix.
For those of you who are only going to be listening, perhaps at home, this is still a very practical "target" plan. You'll probably only have a single pair of the LR/RR speakers, these might be dipole designs, and they will get the same signal as your side speakers, perhaps at a somewhat reduced level. It's once again a matter of "trust your ears". Take an approach and try it out. You can't beat the practical lessons gleaned from experimenting with several alternatives before you decide the leave things more or less permanently in place.

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Optimum Quadraphony
opt quad
Typical Quadraphonic Setup -- 4.2 Channels

Ah, the glorious days of Quad! A time of breakthroughs in audio, enveloping sound all around you, a band performing right in your own living room, audio that has not been matched since! That's not quite the way it was. Unfortunately there were two major dilutions which quickly dissuaded most listeners from taking that expensive step of doubling up on speakers and amplifiers. The advertising promised what the reality wasn't able to deliver. One of the problems was that most of the recordings released in albums marked "Quadraphonic" were actually only stereo. They relied on one of a handful of "Matrix Quad" bootstraps to turn the actual stereo two track recordings into four separate signals for your quad amps and speakers. In truth, they were out to get something for nothing. Pure corporate greed and larceny, nothing new here. We'll cover the matrix story elsewhere. Just keep in mind that in limited cases, like the use Dolby put it to for film soundtracks, such a scheme can be useful, especially when constraints prevent a real discrete method from gaining widespread use.
But for most music applications the truth is not far from what your brain is telling you: it won't work. Well, it still can create some nice, pleasant musical effects. And with certain kinds of music the very best "logic decoders" can do somewhat better than that. Let's ignore the question since there now are several fine systems available to present excellent multichannel surround to the home listener, the newest being the DVD-Audio format.
The second major dilution that crippled the early quad systems is the faulty plan of distributing this doubled information in a way we can readily hear and appreciate. The folly of "Obvious Quad" has already been covered up above, in Digression I. That provided the second of the "one-two punches" that spelled the end of quad. Until now. This time we've started by basing the music surround systems on the well-proven film surround designs. We're not as likely to fall into either trap, as we will have truly discrete channels of very high fidelity indeed, and will distribute these channels around the room in an extension of good filmtrack practice. For musical purposes there's still a lot to be said for four track versions, or Quad. Most home systems don't have particularly good center speakers, often making do with the "phantom center" that any ordinary stereo can do. And many musicians seem less interested in plopping the vocalist automatically in a center channel, and don't even have much need for that channel.
Above is a really effective way to monitor and listen to Quadraphonic recordings. Had this been the way it was done in the 70's, and had the manufacturers avoided their phoney early matrix systems, quad might have had a real chance to survive. Think of what a wonderful backlog of masters we'd have now to place on our new DVD-A's!


min quad
Minimum Basic Quadraphonic Setup -- 4.0 Channels  

There are two changes in the next plan. Many homes and studios don't have subwoofers, so we've left them out. Won't change the directionality one whit, a matter of wide fidelity rather than stereophony. Also we've placed the side speakers back to the theoretical optimum, directly opposite one another on both sides. For music this is certainly the preferred choice, and the original quad was nearly always a music, not film sound, method of reproduction. Since we've covered the LCRS four channel systems like Dolby Stereo above, now we're looking at home music systems, and the studio setups for making and monitoring such recordings. The other change you may consider to favor music reproduction is to restore an equal 60 degrees between each pair of channels, back to where we started above.


Narrower Basic Quadraphonic Setup -- 4 Channels

But wait a minute, before doing that, let's consider if your listening space is rather narrow for either of the plans above. What should you do, reduce all the speaker spacings all around, or just narrow in the width of LS and RS? We've taken the second approach here, as the change is not a large one. Certainly a smaller scale of any of these plans will work well. You could enlarge one up to the sizes of an auditorium, much like the Theater on Columbia University's campus, described at the beginning of this essay. In our plan above, however, we've narrowed our room somewhat, about 15% from the above variations. And we're going to leave those front two speakers at a 50 degree spacing, since now we'll be moving the LS and RS speakers inwards. So all the speakers have effectively been scaled in sideways from the original 60/60/60 spacings so ideal for music.
Yes, it's true that the side channels now are several inches closer to the listener than either front channel. For this modest difference, no harm is done. You can add a millisecond or two of delay to the LS and RS channels, much as we mentioned above regarding a too-close C channel (remember, at the average speed of sound of 1100 f/s, you'll need about 1 ms. delay roughly for each foot of "inwards" correction). But that may be overkill when the change is so small. You listen to stereo often when the distance to the left and right speakers have a foot or more difference, and yet you still hear stereo. I discovered while trying this out, moving the big Cornwalls in different spots before the final choice was made, that side speakers a bit in can be rather cool when listening to plain old stereo over all channels. If you put the left track on both LS and LF, LS down a couple of dB from LF, and do the same with the right track on RS and RF, something really effective happens, a kind of "ultra-stereo."
It's just the serendipity of the situation, almost something for nothing, which I'd never have guessed "ad hoc", without stumbling on it first. You obtain something rather better than the usual stereo, approaching, but certainly not reaching, the subtleties of true quadraphonic surround sound. It's nice to learn we won't have to discard our stereo-CD's after becoming surround-ready. You can take my word for it on this, although, once again, I'd much prefer to have you work it out for yourself, do some experimentation. And it may inspire you discover an even better way to go!

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Quadraphonic Folly
tetra plan a
Tetrahedral Surround Plan A -- 4 Channels

Now and again the suggestion of "Tetrahedral" channel placement arises, Phoenix like, from the ashes. It usually goes like this: "Say, if we've got FOUR separate channels, why not create a 3-D solid of sound, using a FOUR-sided tetrahedron! We can place one channel in each of the four corners of the 'hedron, use a microphone with four directional elements aiming in each of the four directions, mount the speakers the same way. Then we can have sounds come from any direction at all!" Great! Certainly is a lovely notion on paper. Except there's something worrying here: a speaker in every corner. Haven't we already seen that no matter how obvious an approach this is, it comes up as an argument with "holes" in it, to turn a phrase?
If four independent channels are insufficient to cover a flat 360 degree plane, certainly there's little hope they can cover MORE than that, like a spherical 360 sound space. Good grief (you're right), there's no hope at all (they don't), it sounds lousy. A favored configuration is the above "Plan A" (from Outer Space...? ;^). Note how the LF speaker is located down on the floor, then the next channel, RF is mounted up high in its corner, and around we go, down, up. Neat, huh? Compare the result with the folly of "Obvious Quad" in Digression I above. Only now the angle between each speaker is more than 110 degrees. You liked the big holes in the middle with 90 degree spacing, you're gonna LOVE it -- nearly 120 degrees of pure emptiness! We've destroyed what little "fusion" there existed before in front, as the pair along any wall must span the full diagonal length of that wall. No surprise to find black holes all over the place.
Evenso, there are some benefits to record with such four-element microphones, like the famous Calrec. By matrix manipulations of the sum and difference type we can "extract" the equivalent of a directional mike aimed in any spherical direction. You can capture an event with many recording channels, four per soundfield mike, and then later trim and fine-tune the mike aiming points. No, you can't effectively reposition the mikes, but it still is a most flexible scheme of event capture. If you have enough channels of monitoring, perhaps eight or more (Octophonic Sound, anyone?), and place these into a more modest configuration, you might be able to come up with a workable soundspace of environmental sound.


tetra plan b
Tetrahedral Surround Plan B -- 4 Channels

But if you're stuck with only four channels for reproduction, there's not much more you can do about the up-down, or "third axis". Here's another scheme, Plan B, above which tries to square the circle, trisect the angle, invent perpetual motion, and on down to oblivion. Is it just me, or isn't this one kinda nervous making? I mean, would you mind having a large loudspeaker suspended right over your head, aiming down at you? Great for "the voice of God" effects! Of course one of the six channels in IMAX theaters does exactly this. At least they have five other tracks, so the main expanse of the screen is better handled that the above plan, with only three channels left to define 360 degrees. Yes, that's gonna lead to more of those blackholes, who says we haven't discovered "all the missing dark matter" in the Universe?

In any case, I've put the cart in front of the horse here. Our hearing apparatus is very weak at detecting up-down movement and locations. I could have added another experiment to try in Digression II above. It's easy enough to do. With your two channel stereo turn your head over to the side by 90 degrees, one ear aiming down, one up. Now listen to the two speakers, one effectively "above" your head, the other "below". What's wrong with this picture? Do you hear much separation? Close your eyes and listen carefully. Play some "ping-pong" stereo material, or have a friend rotate the balance or level controls so the sound definitely moves back and forth between the speakers. How's it sound? Straighten up and compare. Unless you do have an extra ear on top of your head, I suspect you'll come away from this a little less excited by the prospects of 3-D spherical surround sound. I was. The test here works better outdoors, where there are no clues from reflections on walls or ceiling. More honest test that way, unless you have an anechoic chamber handy.
The other suggestion for a test, with a tiny noisemaker, a "cricket "or "clicker" should be repeated here. Have the sounds be moved from below to above at the same left-right angle. See what differences can be heard. Try it outdoors. Compare with front rear motion or arbitrary jumps, and near to far motion and jumps. We have to be sure about what we can easily detect and what we can't. Our eyes will deceive us, both ways: we can hear "phantom center" sounds between two speakers equidistant from us, our eyes tell us the space is empty. Our eyes see speakers above and below, but our ears are not so sure it's mostly guesswork. It's by coming up with concepts that look good to the eye we blunder both ways. We come up with plans that can't be heard well, and never consider the plans our ears will really enjoy. It's another case of how easily we can fool ourselves, especially if we've invested a lot of time and money in an idea resting on acoustic folly. Please trust your ears as you navigate these rocky narrows. Do everything "double-blind", with verification by others who seem to have excellent hearing. Find out what works for you, in any case, even when the lights are out, and it's every ear for itself...

There are other very important issues for good surround recordings that we've not been able to cover here. Many of the techniques and philosophy that go into fine (2-track) stereophony will carry over directly into the newest wrap-around systems. If any of the better available setups, like some of those above, is adopted as the basis for our favored system, instruments can be placed in many more apparent positions than ever possible before with two tracks. Attending a live concert in a superb venue like Carnegie Hall, and sitting fairly closely, you'll hear a wide arc or "curtain of sound," and many acoustic reflections and reverberation coming at you from all directions. Your ears will pick up the original sound placements up in front easily, and will certainly hear a large part, but not all, of the ambient information. Such clues of size of the room and shape are the ones to try to capture on a recording. Don't worry about some theoretical ideals of "completely reconstructing the listening space." You can't. Not even with 7.2 channels, you can't.
So don't fret about what will be lost, don't assume you can recreate such effects unambiguously "a posteriori," using a multitrack master and a fine surround mixing studio. Go back to the basics. Get the overall balances between the sounds right, that's not going to change. Set the equalization and wet-dry mods where they sound best, the same as usual. Let the reverb come mostly from the side channels, along with at least some of the instruments (don't waste LS & RS just on reverb/echo). Some reverb or ambience ought be heard from the front, too, and probably it should use shorter delays and decays, and a bit less level. You can use neat toys like Psi-Networks (for 90 degree constant phase shifting) without worries of incompatibility and corruption as existed with all the pseudo quad matrix schemes: SQ, QS, RM, etcetera (I'll have more on matrix networks and early quad systems and my trial by fire with SQ in a related page here soon). You can use the widening of "sound-shuffling" processing to great effect on 5.1 channels, it's nothing to be tossed aside just because we're working with more than two channels. The transition to full surround is simply a move to a superset of everything else we already know, from creating, engineering and producing, to the "all-enveloping" new playback systems at home. We don't have to begin all over again. This is NOT rocket science!
I've been mixing most of my music in surround sound since the early 60's, and have saved all the master tapes in good condition. Now that DVD-A has been standardized, I expect to have a LOT of fun making these available to you. Yeay!! I love the liberating feeling to compose FOR surround, actually conceive it as a part of the creative process, not something slapped on later like a coat of paint. 5.1 or .2 is going to be WONderful for the recording arts and sciences. Much much more important than 96k/192k sampling idiocy at a hype-y 24 bits. (Did you hear that? Did I hear what? You know, the tighter ambience, contoured timbral nuance and extended silky imaging? Oh, right, of course, I was just about to mention it: a SPLENDID new suit of clothes, your Majesty!) Spend that extra DVD bandwidth wisely: give us multichannels! Ahem. That's something everyone can hear as an improvement. Let's not "blow it" this time, people, defending some theoretical folly or visual chauvinism, as was done in the 70's. Let's get it together this time.
Pep talk is over. Hope you tend to agree. Be back again with more soon. And thanx for reading all of this!

--Wendy Carlos

© Copyright 2001 Wendy Carlos -- All Rights Reserved.

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