Previewing 'Gravity': Alfonso Cuaron Turned to Dolby's Atmos-Equipped Screening Room

"It's very quiet, there’s no exterior noise, and you are fully isolated so that you only hear the speaker and room acoustics," says Dolby exec David Gray.

For previews of his space thriller Gravity, director Alfonso Cuaron wanted audiences, including the press, to see the film in a theater equipped to show the version mixed in Atmos, the immersive new sound format from Dolby.

But since Atmos is still relatively new, and Warners doesn’t have support in its screening room, many of the previews were scheduled for the Atmos-equipped screening room at Dolby's Burbank offices.

I have seen Gravity twice, and I did find a noticeable improvement in the sound experience when I saw it with Atmos sound at Dolby. The construction of this screening room was an extensive effort, so it seemed a good time to revisit the story behind the room with the man who led the project, Dolby’s vp content services, David Gray. (Gray also led the Atmos installation at the Dolby Theatre at Hollywood & Highland).

The Dolby screening room in Burbank was carefully constructed in 2002, not long after the audio giant purchased its building on West Alameda. Gray maintains that this remains one of the best screening rooms in Los Angeles from a sound perspective.

"It’s very quiet, there’s no exterior noise and you are fully isolated so that you only hear the speaker and room acoustics," he told The Hollywood Reporter. "It’s not tainted by anything else. The acoustics are designed to mitigate standing waves and create a smooth frequency response in as many seats as possible."

The building, though, is roughly one mile from Burbank Airport, so Gray relayed that the team spent days on the roof during the planning stage, recording flight patterns, loudness, and the frequencies of the noise.

In the end, they constructed a floating room -- a room within a room -- on the top floor of the three-story building, which allowed the company to raise the roof by roughly nine feet to get the desired height. The company also had the building’s structure reinforced before construction.

STORY: Astronaut Buzz Aldrin Reviews 'Gravity' 

The floor sits on two-and-a-half-inch neoprene (dense rubber) pucks -- which basically act as a shock absorber -- arranged in a grid. On top of that is a layer of steel, and on top of that is four inches of concrete. "So when the structure vibrates, it doesn't vibrate the main building, and vice versa," Gray said, admitting that he has even been in the room during earthquakes, and remained unaware that anything had happened.

A three-wall system was also constructed -- there’s an outer wall, 10 inches of air, another wall, four inches of air, and a third wall. The two interior walls are on the floating floor. "There's more isolation than most theaters because more sound needed to be kept out," Gray explained, adding that the sound also need to be kept in, as the theater is just steps from other offices in the building.

Gray admits it cost "in the millions" to construct the 56-seat (when a mixing console is not in use) theater. "Screening rooms of this level are fairly rare. It's too expensive for most exhibitors," he said, adding that  movies theaters with floating floors are extremely rare, though double walls are becoming more common in new constructions. This sort of construction is more common on studio dubbing stages, he said.

The Dolby Burbank screening room's technical infrastructure has been upgraded in recent years to support Dolby 3D, and in 2012 to produce Atmos sound.

The sound format was developed to create a lifelike experience by lining speakers along the theater’s front, rear, and side walls, as well as overhead. It can play up to 128 channels of sound at once, meaning that sound can be placed -- and moved -- more precisely.

FILM REVIEW: 'Gravity' 

The Dolby screening room was originally upgraded for demonstrations of this new technology, but it soon became an additional mixing room. In 2012, Dreamworks Animation decided to release Rise of the Guardians in Atmos, but at the time only Skywalker Sound in Northern California had an Atmos-ready mixing stage. Gray related that Rise became the first Atmos release to be mixed at Dolby.

Gravity was mixed at Warners by Academy Award nominated re-recording mixer Skip Lievsay in collaboration with re-recording mixer Niv Adiri. Academy Award nominated Glenn Freemantle was the supervising sound editor and sound designer.

You need to check local listings to find a theater playing Gravity in Atmos when it opens on Friday, but a listing of theaters with at least one Atmos-equipped auditorium can be found here.