Gravity: Making an Oscar-winning soundtrack

posted on Sunday, 9th March 2014 by Steve May

home cinema  Dolby Atmos 


"Everything is layers," explains sound designer extraordinaire Glenn Freemantle. "When I begin to conceptualise a soundtrack I like to think of all the elements individually, work out how one thing sounds at a time. If you try to imagine the sound of a film in its entirety it becomes a muddle…"

Freemantle is explaining the process that went into creating the award winning sound mix for Alfonso Cuaró's space thriller Gravity, an approach that has seen his trophy cabinet steadily fill.  "The entire soundtrack is bespoke," he reveals. "We created every sound you hear. It's much like what we did on Danny Boyle's 127 hours. 98 per cent of that movie was ADR. All the original sound was thrown away, we had to completely recreate the sound of that canyon. When we started on the Gravity soundtrack, we were just working with pre-viz, nothing had actually been shot."

The effort and imagination that required was clearly more than worthwhile. Gravity has proved a worldwide sensation, winning Freemantle the 2014 BAFTA for Best Sound, and more recently the 2014 Oscar for Best Sound Editing. The movie is now available on Blu-ray providing custom installers with what's likely to be the best showroom demo content of the year.

"Alfonso rang me up early in the process," recalls Freemantle. "He said he wanted to put a concept together to show the studio, to go to the next stage of making the movie. So literally at that point and at that meeting, we came up with the concept of how we were going to do the sound." The idea, he says, was to make viewers feel they were actually in Sandra Bullock's suit. "It was all about vibration and touch, experiencing weightlessness from Sandra's point of view, from her heartbeat to her tinnitus."

The sound design doesn't stop moving, from the beginning of the film to the end. "This isn't a movie that uses sound for sound's sake," he adds. "It's about using sound to create emotive content to pull you in to the story, to take you on Sandra's journey."

Inside CI caught up with Freemantle at Dolby's London HQ, for a special screening of the film in the advanced Dolby Atmos surround format. It proves to be an exhilerating experience. Freemantle confides that the Atmos work was done after the conventional 5.1/7.1 mixes, which is a reverse of the normal workflow. More usually, a film soundtrack will be created in Atmos, which then provides the 7.1 downmix.

The technology behind Dolby Atmos
Dolby Atmos isn't a channel based sound system in the conventional sense, it's object based, and uses a process known as adaptive rendering. With object based steering, sound engineers can place an audio element anywhere spatially, with a precision impossible in conventional channel mixes. Audio elements are not locked to any particular channels. Instead, they are stored with virtual position metadata and are assigned positions dynamically during playback, depending on the arrangement within any given theatre. The result is a totally immersive soundfield, regardless of the size of the theatre and its speaker deployment.

"Gravity has got Dolby Atmos written all over it," says Freemantle. "Because it is literally about space, we were going to take full advantage of that. While we can create a similar design in 7.1, there isn't a system out there that offers the same creative freedom. With Dolby Atmos we could take the concept behind the film to a new level. And that's what I hope we've achieved."

Of course, Dolby Atmos audio doesn't have to be all-pervasive and complex. An Atmos remix of The Artist, which won an Oscar for Best Original Score, transpires to be largely monophonic, opening up only subtly during a dream sequence and in the final moments.

Dolby Atmos cinema returns to London
Unfortunately, commercialising Dolby Atmos has not been easy. Equipping cinemas with the sound system is an expensive business. Currently consumers can only hear Atmos at the VueXtreme auditorium in the Glasgow Fort shopping park, and the boutique Olympic Studios cinema in Barnes, London. Central London did have the Empire Leicester Square, however shortly after installation the decision was taken to close the venue's 1330 seat Screen One and redevelop it into two smaller screens. The new flagship screen will be an IMAX branded 750-seater, supplemented by a second smaller 400-seat cinema. While owner Empire Cinemas has made no official announcement, Inside CI has it on good authority that this second screen will be Atmos equipped, giving the sound format back a central London home.

At present, there are no plans to bring Atmos into the home theatre space, but this is surely a case of when rather than if. Rival 3D sound format Auro-3D is already available on the Datasat RS20i and LS10 processors, and Auro-encoded Blu-rays are promised for later this year.


Steve May

Inside CI Editor Steve May is a freelance technology specialist who also writes for T3TechRadarHome Cinema Choice, Trusted Reviews and The Luxe Review.

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