The sound of Gravity

An international audio team on an out-of-this-world film, Kevin Hilton explores the sound of Gravity.

Despite being behind the Warner Bros shield and featuring two big name stars, Sandra Bullock and George Clooney, Gravity is an example of the more international flavour of Hollywood these days. It was directed and co-written (with his son Jonás) by Mexican director/producer Alfonso Cuarón and is a co-production between WB, Esperanto Films and British company Heyday Films.

UK input is strong on the audio side, with composer Steven Price and sound designer/supervising sound editor Glenn Freemantle of Sound 24 both a major part of the production.

The use of audio and music set Gravity even further apart from the bulk of recent releases. While the stereoscopic 3D images and visual effects grab the ocular attention, much of the film’s emotional punch and sense of tension comes from the aural.

“The idea was to be more realistic and true to some of the science of the situation,” Freemantle explains. “So the sound is based on how she hears and feels everything, which brings her and the audience into the middle of the action and makes you part of it.”

By ‘she’ Freemantle means Dr Ryan Stone, the character played by Sandra Bullock. In another break with how most modern films are constructed, Gravity is on the verge of being a one-person show; George Clooney’s performance as old-hand astronaut Matt Kowalski is almost a supporting role and other ‘characters’ appear only as voices in Stone’s headset or on space capsule radios.

Different approach

There is a near experimental edge to Gravity; there are the impressive backgrounds of space and the Earth but for long sequences the frame is filled with either Bullock’s head in a helmet or close-ups of her inside space stations. The 3D effects go someway to maintain the interest but because the sound and music are used in a more intimate way they make a more subtle connection with the audience.

“The contact is there for her with the voices,” says Freemantle, “but also in when she moves. When she touches something we hear it. The whole concept was to feel sounds through vibrations, because the space suits are full of air. There’s breathing as well as the radio signals, all of which connect to her.”

To achieve this Freemantle recorded a variety of sounds as vibrations through different surfaces, from manufacturing units at the General Motors factory, to objects submerged in water and fitted with contact mics and hydrophones. This built up to “thousands of different vibration sounds”. Also part of the many tracks were four hours of what Freemantle describes as “chatter” from people who had worked on the space programme.

There are more expected sound effects as well, rocket boosters, collisions and explosions, which, like the vibrations and voices, are dotted round the audio picture through the Dolby Atmos spatial system. Gravity had been in the movie-making works since 2010 and Freemantle was aware of Atmos while it was still in development around the same time. He realised it was perfect for the film and used it extensively, even breaking the convention of tying dialogue to the centre channel.

“Sounds are moving around all the time,” he says. “Right from the beginning we have mission control [voiced by Ed Harris] on the right hand side of the screen but the voice moves as they [Bullock and Clooney] move. It gives us directional sound in relation to where things are on the screen.”

Freemantle says Munro recorded as much as possible on set, given the constraints of the space suits, but adds that there was a lot of ADR, particularly for breathing noises to communicate anxiety.

Tracks were recorded on to Pro Tools and mixed into 7.1 and 5.1 at Warner Bros De Lane Lea in London. Later alterations, caused by changes to visual effects, were made to the mixes on the Powell Stage at Pinewood; the Atmos tracks were mixed at Warner Bros in Burbank.