You're Surrounded, Part One: Surround Sound Design In Theatre

If you’ve been paying the least bit of attention to this series of ramblings, you’ll have realized that my formative years, aurally speaking, were in the late 1960s and early 1970s, a particularly rich period for innovation, both in terms of music and audio development. Of course, there were missteps along the way, and one of these was the great surround sound debacle, concerning the attempts by various record companies to foist their own version of quadraphonics, as the fledgling technology was known in those days, on a gullible public. Sansui developed a matrix system called QS; Columbia Records and Sony, not to be outdone, developed their own matrix-based system called, with stunning originality, SQ, and JVC in partnership with RCA came up with a carrier-based encoding and decoding system called CD-4. I witnessed demonstrations of all three of these and can confirm that none of them was particularly effective, and eventually, thankfully, they all faded away as home audio enthusiasts (and their homemaker partners, no doubt) decided that two speakers was quite enough, thanks, and record companies and hi-fi manufacturers decided that producing one set of recordings and equipment that everyone wanted to buy was a better bet than producing three different systems that no one wanted to buy. And that was that for a good few years.

 

Being a long-haired hippy, fully paid-up nerd, and badly paid-up theatre sound man, I eschewed the esoteric world of high-end hi-fi and was already experimenting with surround, using what came to be known as the Hafler Hook-up, after David Hafler, the American audio engineer who popularized this particular kludge. It was a simple modification, consisting of adding an extra pair of speakers behind the listening position, wired in series, and connected to the positive terminals of each of a stereo amplifier’s speaker outputs, thus collecting any out of phase signals inherent in the original recording. It was not always successful, but could sometimes provide startling effects. At the time, I had access to a Nikko amplifier that had two switched sets of speaker outputs, so the hook-up was extremely easy, and I also had a copy of Jimi Hendrix’s album Electric Ladyland, containing the track “Voodoo Child (Slight Return)” on which Hendrix, Eddie Kramer, and Chas Chandler had had a lot of fun with extensive use of panning, ADT, tape echo, and other effects, and which I reasoned had to have quite a bit of out-of-phase information to extract. I set the system up in the theatre’s sound room with a pair of Tannoy Lancasters as the main left-right pair and a couple of infinite baffle extension loudspeakers that were lying around as the rear surrounds, lowered the stylus (Garrard 301 turntable, SME 3009 transcription arm, Shure V15 Mk III cartridge—eat your hearts out, audiophiles) onto the appropriate track, and had a very interesting Jimi Hendrix experience indeed, no mind-expanding drugs needed. I was sold on seeing what I could do with surround in a theatre environment, and I’ve been experimenting ever since. You can experiment in exactly the same way: see the how-to section at the end of the article.

 

Luckily, two of the three theatres within my remit had the possibility of routing different sounds to speakers situated throughout the space, and I was soon flying planes around the auditorium, sending artillery shells whooshing over the heads of the audience during battle scenes, and generally surround-sounding the heck out of any show that seemed to call for it, and when my colleague, Alastair Goolden, and I designed and built a new mixing desk for The Bristol Old Vic’s Theatre Royal, we built a patchable quad-pot into the system.

 

Multiple two-track tape machines and a set of fully assignable input and output channels gave us the facility to place sounds almost anywhere in the theatre, and the ability to fire more than one tape machine with a single remote button meant that we could theoretically have run in-sync eight-track playback, for as long as the Revox A77s’ speed stability allowed, anyway. 

 

The hi-fi world soon forgot about surround, but my interest remained, and through a series of chance encounters at trade events, I came across the work of Michael Gerzon and Peter Fellget and their exploration of single-point capture of a spherical sound field. From early experiments at Oxford and Reading Universities, the much-misunderstood (at the time) theory of Ambisonics slowly leaked into my consciousness, and when, in 1979, I was given a private demonstration of a B-Format surround recording of The Last Night Of The Proms, the culmination of a series of classical music concerts given at The Royal Albert Hall in London, I was totally hooked. The demonstration got off to a shaky start, with the imaging being very odd, until Calrec’s chief microphone man, Ken Farrar, demonstrating the system at its HQ in the impossibly picturesque Yorkshire town of Hebden Bridge, got up and turned a knob marked “rotate” on the front of the controller, and suddenly the entire Royal Albert Hall—audience, orchestra, and all—pivoted through 180º, and I was sitting in the middle of the audience with the orchestra in front of me and cheering and clapping crowds around, behind and above me as a patriotic anthem ended with a flourish.

 

Someone coughed behind me, and I turned around to find that there was no one there, the cougher having been faithfully captured by Calrec’s Soundfield microphone. I missed three trains during the rest of the demonstration, and the subsequent discussions, and returned to my employment with the Royal Shakespeare Company (RSC) to write an impassioned memo about the possibilities inherent in using Ambisonic technology for theatre sound. Needless to say, the cost of the technology was way beyond what a subsidized theatre company could afford, but I progressed and pushed, and eventually was given permission at least to explore how we might use the system for positioning recorded sound in a smaller venue. 

 

A plan for a special control system whereby mono sounds could be placed in a spherical sound-field was drawn up, and parts were purchased to build a system for the RSC’s small-scale touring venture, but the acquisition of the manufacturing rights for the commercial development of a domestic Ambisonic system by a UK government-backed organization called The National Research & Development Council (NRDC) put an enormous spanner in the works, and without the help of the boffins who were now focusing their energies elsewhere, the project foundered. The NRDC system did eventually see the light of day as a horizontal-only surround system, but for some inexplicable reason, the commercial outlet deemed suitable to market the system was not a national chain of hi-fi stores, but a chain of high-street drug stores. Additionally, the paucity of material suitably encoded for surround playback, barring a few specialist record labels and some rare radio broadcasts by the BBC, meant that very few people actually purchased the system, and so that too died a miserable death. 

 

There was an upside even to this, because we discovered that the very small speakers used in the system were rather good, pretty robust, and perfect for use as auditorium surround speakers, and we purchased a large number directly from the manufacturer to provide surround sound for the RSC’s epic ten-play cycle based on the Oresteia legend, directed by John Barton and known as The Greeks, at London’s Aldwych Theatre, in 1980. When Troy burned, we surrounded all three levels of the theatre with the sound of the fire, and very effective it was, too. (That production also featured ‘Baby Orestes,’ a rather obese doll, fitted with the stripped-out guts of an elderly mains-powered wireless mic receiver rigged to run from a 12V sealed lead-acid battery along with a small amplifier and speaker, with the transmitter fed from a tape machine via a D.I. box. Baby Orestes was carried around the stage by various actors and cried on cue from wherever he happened to be. Common fare these days, but this was almost 45 years ago, and we were rather proud of it at the time.)

 

The years passed. In theatre, we continued to do surround in the standard way, routing sounds and delays and reverbs to speakers in, around, and above the audience in a way that the film industry couldn’t hope to emulate, despite all the advances in surround encoding by Dolby and others. My interest in Ambisonics remained strong, and in 1988, I bought one of the first truly portable battery-powered Soundfield microphones, the ST250, and used it, initially, almost exclusively in stereo mode to expand my sound effects collection and for some music recording as well. Decoding the B-Format signal to surround was still a hardware process, and the decoders were too expensive for me to afford, and truly portable four-track recorders were non-existent. You could cobble something together with a ProTools rig in a truck but not really anything affordable that you could trek off into the wild and make surround recordings with, without a team of porters to carry the kit. 

 

That changed for me following my discovery of a company making some rather special audio software called Metric Halo. I’d bought both the audio analysis program, SpectraFoo, and the ChannelStrip EQ/Dynamics plug-in products devised by genius brothers B.J. and Joe Buchalter. A visit to the MH facility in upstate New York included a conversation on how I’d really like to have a portable multi-channel microphone interface that I could hook up to a laptop, sling in a backpack, and make multi-channel recordings anywhere without the need for anything other than a couple of spare laptop batteries. Not long after, I was asked if I’d like to join the beta team to test the first FireWire-powered eight-channel audio interface. I gladly accepted, and my Metric Halo 2882, in its current expanded incarnation, has been working perfectly for me for almost 15 years now. 

 

Possibilities opened up. I could carry all the kit with me and make surround recordings anywhere I wanted, and I did. The first recordings were made, literally, in a field, while an obliging light aircraft pilot hedgehopped around the area for the price of a full tank of gas. It was also now possible to transcode the four-channel B-Format signals to stereo, mono, or a number of other formats, using a DAW or, as we later discovered, Richmond Sound Design’s AudioBox, with its complex matrixing controls, and surround effects began to creep into my sound designs.

 

But there were, by now a number of young pretenders to the surround throne, and we’ll look at them and their suitability for theatre sound design in the next part of this article. In the meantime, here’s how to recreate my experiments with surround from the 1970s.

 

 

If you’ve got a system that allows you to route three tracks of audio to different loudspeakers, you can do the same experiment I did back in the early 1970s, with the same track and some basic audio processing software. I used the excellent TwistedWave to process the audio and produce the screen grabs, but any halfway decent DAW should be able to cope. 

 

First, make sure you’ve got the right track: this particular one has been released under a variety of names, but the actual track from Electric Ladyland is indeed titled “Voodoo Child (Slight Return).” It was also released as a single under the title “Voodoo Chile,” so that’ll do, and that’s the track I’ve used for the demonstration. Next, you need to find a version that hasn’t been re-mastered. If the waveform display looks like this, then you’ve found the right one:

 

 

The version from iTunes will work, but it’s been fiddled with and compressed to death, so the results aren’t as spectacular.

 

Okay, now you’ve got it loaded into your DAW, so select one of the channels—it doesn’t matter which one—and invert the polarity, like so:

 

 

Nothing will change in display, but you’ll now have a stereo track where one channel is 180° out of phase with the other. 

 

Next, combine the two tracks into a mono signal:

 

 

And you should end up with a waveform that looks like this:

 

 

That’s the out-of-phase information that’s present in the original recording. Play it, if you like, and see what you can hear. If you end up with nothing, then you’ve been working with a mono version in the first place, silly you! (Incidentally, this is an old trick that can sometimes be effective at removing a vocal from a recording for a sort of karaoke effect. Unfortunately, it also removes a lot of other stuff as well, so it’s not recommended.)

 

Now comes the fun part: load the original stereo track and the mono out of phase track into your favorite DAW or theatre playback system so that both tracks will play in sync. Route the stereo track to front left and right and the mono track to the rear speakers, set levels, and hit play. Good, isn’t it? Hear that guitar whiz around your head and try intoning, “Wow, the colors, man,” for the full psychedelic experience.

 

If you’re not a Hendrix fan, try to find a purist Blumlein (stereo pair comprising coincident figure-eight microphones arranged at an angle of 90° to each other) classical recording made in a cathedral or other reverberant space, and use that instead. Believe me: it’s cheaper than buying an SACD player.

 

John Leonard is an award-winning designer who has been working in theatre sound for over 40 years. In his spare time, he records anything that makes an interesting noise in high-definition surround sound. His sound effects libraries are available online at www.johnleonard.co.uk/immersive.html. Live Design readers receive a 30% discount on all libraries, excepting the monthly Dollar Deals, with the code LDM30.