Interview with Ioan Allen

The Dolby Film Sound Revolution:

Looking Back and Looking Forward
with Audio Pioneer Ioan Allen

Second of Two Parts

by Leslie Shatz

Go To Part 1

After working in artist management and record production, Ioan Allen joined Dolby Laboratories in 1969 and was largely responsible for the origination and development of the



Ioan Allen

Dolby Stereo film program. Later, he participated in the development of Dolby Digital, the company’s multi-track digital film sound system, and he is now working on their digital cinema and digital projection technologies. Part visionary engineer and part ambassador of good will for Dolby Labs, he talked in our last issue about the genesis of Dolby Stereo and the issues the company faced in helping the motion picture industry adopt it. In this, the second part of our conversation, we discussed the end of silver-based, analog optical tracks, the advent of Dolby Digital and the conundrum of film sound loudness.

[Until recently, optical soundtracks were exposed and read by the infrared component of white light. This standard is now in the process of changing. The new standard is the high-magenta soundtrack, which will eventually give way to the cyan (blue-green) soundtrack. Dolby Labs has patented a combination of cyan dye track and red light (the compliment to cyan), which they have donated, royalty-free, to the industry. Dolby Labs and Mr. Allen are actively involved in the implementation and technical development of this program and he is a member of the DTC group (Dye Track Committee) made up of laboratories, stock manufacturers and other interested parties.]

Ioan Allen: First, let’s talk about cyan. Back in the days of black and white film, silver was everywhere. When we switched to color film, dyes replaced silver, but the black dye is almost transparent to infrared light, which is what a conventional soundtrack reader on a projector works with.

Even though the projector uses a white light bulb in the track reader, it’s the infrared part of that energy that’s being read.

Yes. So what happened was in the 1940’s, when color film was introduced, they decided to put a layer of silver on top of the dye in the soundtrack area of the release print. This process is called redevelopment, also known as track application or re-application, where a wheel or now a spray deposits a nasty goo in the track area of each print, and then adds the silver layer on top of the dye. That’s problem number one — to get rid of hydroquinone and various o

Our job as format designers is to provide a clean canvas and all the colors. Only you can decide how to paint the painting. We should only make sure there are no constraints.

ther nasty chemicals needed to create that track, because in this day and age they’re environmentally harmful. Problem number two is that tungsten bulbs — conventional white lights that are used in the projector readers — could become unavailable. It’s possible that people won’t make them in a few years time. In the U.S. certainly. And the quality of those lights has been getting worse. The filaments are not lined up properly, like they used to be a few years ago. There were huge quantities of those lights made for car rear lights, but now car lights are bright red LED’s [light-emitting diodes]. The answer to this is to use a bright red LED in the projector. This is a stable technology that is going to last, unlike the tungsten bulb. With a red LED in the projector, and a cyan-colored, dye-based track, you don’t need to put silver on it, and it plays just fine. The long-term target of the laboratories and the stock manufacturers and the theaters as well, is to go over to red light with the cyan soundtrack. Another reason the theaters like it is because the red LED has a much longer life than a tungsten lamp and will never have sudden-death failure. The LED just gradually fades away, whereas a tungsten light is just like a house light — it can suddenly snap off and the movie stops. But we can’t go to cyan soundtracks until at least 85 percent of the theaters in the country have installed red LED’s in their projectors.

In this country, I think we’ve probably reached about 50 percent red lights. All new projectors for the last eight years have had red lights on them, so it’s growing. In the meantime, when you have a mix of white lights and red lights on projectors, you want to minimize the distortion and get a print that plays everywhere. So we changed the color of the dye underneath the silver on conventional prints to what we call high magenta. Magenta is now the color you’ll see underneath the analog silver. This is an interim step, which allows the track to play on all projectors.

But now the analog track doesn’t play perfectly under either condition, isn’t that right?

No, a high magenta track plays perfectly on red or white. But a pure cyan track doesn’t work well with white light. It gets softer by about 10 db. It falls right away.

You can get away with it if you crank the fader up, but it’s not a pretty thing to do. Hopefully, when you get to 85 percent of the theaters equipped with red lights, and then you do a full commercial cyan release without the silver application, that will trigger the last 15 percent to change over. It’s only a few hundred bucks, not an expensive thing, to change over to a red light.

My concern is that one of these cyan prints is going to end up in Ulan Bator or some third-world country somewhere where they barely have a projector and the sound will be completely unintelligible and…

It’s a difficult program, but I think it’s really worthwhile from an environmental point of view. We’ve been at it now for five years. It’s an elusive target, but I think it’s important.

Film is a universal language, thanks to what are now considered primitive technologies. Perhaps while we’re heading somewhere technologically more sophisticated, we’re leaving behind the idea that everyone will be able to watch our films with equal ease.

Yes, but by and large, with international distribution, there are multiple sound negatives printed for the different language versions. The only danger you get into might be Ulan Bator where they subtitle it, and if the English language track plays low, it’s not an absolute disaster. You can just crank it up and hear the music.

The next revolution after the SR analog soundtrack was the Dolby Digital soundtrack. How did it come about? Were you guys sitting around saying, “We’ve got to get into this digital thing, or else we’re gonna be dead”?

It’s the next logical step. The SR soundtrack sounds just fine for nine films out of ten. It’s everything anybody could want artistically. But some people want even more dynamic range than SR offers. Some films want stereo surrounds, and nowadays even three channels of surrounds. In addition, the analog track can still suffer from abuse in a bad theater, where you finish up with a lot of snaps, cracks and pops, and it requires occasional maintenance — checking that the light level is correct and that the film path is in the right location. So finally, around the late 80s, it became apparent to us that the public believed digital was better, rightly or wrongly. They believed that their first generation CD’s were much better than a cassette could ever be, which was probably wrong, because the first generation CD’s had really bad D-to-A [digital to analog] converters, and a well-recorded cassette really sounded excellent. But that was the public perception. So all of those things led us to say we should do digital.

The first thing was to decide where to put this new soundtrack physically on the release print. In order to do that, we put a length of slug, black leader, in between the trailer and the feature in release prints in theaters across the country. I think we did about a dozen theaters and left it there for a hundred or two hundred plays or so. In one theater the leader was actually played a thousand times. Then we got all the black slugs back and examined them to see where there was the least wear, least scratches, least dirt. Our conclusion was that the best place to put the digital track would have been across the frame line, between frames [perpendicular to a conventional track] because the film is moving very slowly as it goes through the gate, making it easy to read data there. On a 1:85 release that would work just fine. There would be limitless bit capacity in that area. The problem is scope films, where there is no frame line. We would have had to alter the aspect ratio to create a space between the frames, and that would mean changing the aperture plates in every theater in the country, and that was just too much.

Worse than that, people would just play it with their old aperture plates, and you’d start seeing inter-frame data projected across the top of the screen. So the next most attractive place was in between the sprocket holes.

Now you’re moving from an analog technology, which was Dolby’s field of expertise, to a mathematical technology with data compression, error correction and such. That’s a whole new deal. Was Dolby set up for that?

We were already pretty expert in data compression in other fields. Dating back to the mid or late 70s, we’d been involved in satellite communication systems. AC-3 [a mathematically-based data compression scheme used by the chips in all Dolby Digital cinema equipment] is son of AC-2 and grandson of AC-1, which are technologies that have been out there for some time and used for audio communication in landline satellites and other fields. AC-3 is more sophisticated because it’s a multi-channel system.

How many theaters are equipped for Dolby Digital, worldwide? Are there still theaters in mono?

It’s reckoned that there are about 120,000 theaters in the world and I think something like 50,000 are digital theaters. In the U.S. there’s somewhere around 35,000 screens, of which 14,000 are Dolby Digital. My guess is there’s still a couple of thousand mono theaters in the U.S., as well. [Sony estimates 8,334 screens for its SDDS system worldwide, and DTS claims 20,376 theaters worldwide.]

Would you say that Europe is more advanced in the way they’ve equipped their theaters?

Yes, in some respects. I think they are more advanced in their use of automation. [Automatically opening and closing the curtains, changing screen masking, changing sound formats and level, usually between the trailers and the feature.] U.S. theaters are not very advanced in terms of automation, which gets us into the loudness problem.

We are pushing films louder and louder, thanks in part to the greater dynamic range offered by the digital release formats. People ask why films are so loud these days. It’s not like there’s any one reason. Each creative person wants something different, but in the end, what we end up with is more volume.

I think trailers are a bigger problem than features. But I think we’ve gone a long way toward licking the trailer problem with TASA. [The Trailer Audio Standards Association, an ongoing group involved with various different aspects of trailer audio.] What would happen two or three years ago with very loud trailers was that the fader would be turned down to about 4-1/2, as opposed to 7. [The standard level for the Dolby playback

equipment is 7. At this setting the film would be heard exactly as loud as it was mixed.] Since there is no automation, and nobody to turn it up again once the feature starts, the show plays at 4-1/2, or 8 or 9 db lower than it was mixed. As a result, you guys in the creative community said, “Hey, the feature’s are gonna be played too low. Let’s crank up the level to compensate for what we know is gonna happen in the boondocks.” But trailers are now mixed a bit lower, and that’s allowed theaters to raise levels a bit. The fader level in the theater is now possibly at an average of 5-1/2, as opposed to 4-1/2, which is not a great deal but it’s a step in the right direction. I believe in a mandated level on trailers, because they are frequently mixed not by the people creating the movies, but by a third party. But I personally don’t believe in any kind of mandated level on features. The director and the mixer and the sound designer who make them should stand or fall on their own loudness. I don’t believe that should be mandated, it’s an artistic issue.

What about removing the volume control completely from the theater? You could make a case that when the theater owner changes the volume, it’s a form of censorship.

Faders are higher in the big urban centers. We’ve done several surveys over the years, which show consistently that in New York, Los Angeles and San Francisco, the faders are significantly higher than they are in rural theaters. The more you get into the suburbs and the rural districts, the lower the fader and the more offended they are by loud action material.

Oh, a few theaters will religiously do it. That tends to be where the operations manager rules with a rod of iron and says, “Were gonna play it back correctly,” and I believe that’s the thing to do. If you play the film with the fader at 7, and a director’s work is unbelievably loud at fader 7, it reflects on that director.

I agree. I believe that if we could eliminate the fader in the theater, we could come to some realistic conclusion about how loud to mix a film.

I think things are getting better. It’s interesting that when we first got involved with 70mm releases in the late 70s, there was a tendency to get things too loud, and some people would crank up the level on the 35mm optical as well. People thought, “Hey, it needs to be a loud action film to justify going with Dolby stereo.” Then we started getting quiet films like Days of Heaven, with a really subtle use of the optical sound track. I think, to some extent, we’re repeating that lesson now with the digital sound track. People think, “Hey you gotta make it loud, it’s digital,” and out of the morass of loud films come two or three films that really take advantage of low level subtleties. Chocolat for instance had some beautiful subtle sound effects using the digital in a completely different way.

Do you feel you’ve opened Pandora’s box with the Dolby Digital release format?

Just because you’ve got a Ferrari you don’t have to drive at 200 miles an hour. Come on, guys!

Where is sound for cinema going? Can you talk about any advancements that Dolby has planned?

Digital cinema [hi-def video projection] will probably have more channels of sound. I don’t know whether they’ll get used, but there is the potential. People are talking about 12 channels. [Current digital release formats have up to 7 channels for Dolby EX, which is a method of adding a matrixed center surround channel to the current SR/D format, and 8 channels for Sony’s SDDS.] That sounds horrific, but it isn’t really that bad because a couple



Allen at Dolby in the late ‘70’s.

of those channels are for the hearing impaired, or are narration channels, etc. But you can certainly talk about adding half-left, and half-right for big screens, and for very big environments, adding a height channel (as used in some IMAX shows) or even two — top-left and top-right. I suppose you could make a case for having four surrounds as opposed to three.

Is there unlimited bandwidth in the digital cinema spec? Unlimited room for additional tracks or sampling rate and bit depth?

No, not yet. Because in these early days, digital releases are being sent to the theaters on multiple DVD’s and then transferred to a big disk drive array for projection. It takes 6 or 7 DVD’s to hold one movie, and it would be nice to get all the foreign languages, as well as the English version, on the discs. That means that there is a space constraint. This is why a lot of these early demonstrations have used Dolby E. [The newest Dolby product, designed for, among other things, digital cinema.] In years to come, as different forms of transmission take place, with movies being distributed to theaters by satellite dish, maybe there will be room for anything, but certainly in these early days, there isn’t.

Some movies are, some are not. It’s not just the technology but the art that’s put onto the technology. It’s the sound designer or the sound editor and the director who really determine how well that technology is used. Our job as format designers is to provide a clean canvas and all the colors. Only you can decide how to paint the painting. We should only make sure there are no constraints.

The music industry? There’s not very much activity there. I would guess about 80 percent of our business now comes from the film industry.

Isn’t that a big shift? In the heyday of Dolby noise reduction, wasn’t it mainly the music industry?

In the early 70s, it was 80-90 percent music industry and 10 percent film, but it’s gradually been moving toward film, as the music industry has changed. The concept of the old big studio is gone, and we do not make a digital recorder. Those two things together make the music industry a pretty small marketplace for us. It’s a very small percentage compared to film.

As a company, there will always be some area of greatest need where we can develop a technology that’s helpful. Many years ago, it was the analog mult-track recorder and the need for noise reduction. Then, it was the quality of film sound that needed greatest attention. Today, we are heavily involved in developments in digital cinema. Who knows what tomorrow will bring!

Leslie Shatz is a sound designer and mixer. His credits include Ghost, Dracula,
Good Will Hunting, The Mummy and The Mummy Returns. He can be reached via email.

In the first part of this article, Ioan stated that the first Dolby SR release occurred in 1989.
In fact, the first releases were in July, 1987: Robocop and Innerspace.

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