AES Section Meeting Reports

New York - November 26, 2013

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A Rare mid-day meeting of the New York Section drew 25 AES members and 10 guests to the plush Dolby Theatre in midtown for a presentation of the Dolby Atmos Cinema Surround Sound System. Section Committee member David Bialik welcomed attendees and put out a call for nominations. Then the meeting was opened by Section Chairman and Dolby Engineer Ken Hunold, and he introduced his colleague Tom Kodros for the presentation.

Right off the bat Tom dimmed the lights and rolled a demo clip which immersed attendees in a sound scape noticeably more subtle and distinct than many cinema experiences. He then told how the Atmos system is the result Dolby engineers working with film makers to continue to improve on existing surround sound technology. We've all likely experienced 5.1 surround systems in commercial theaters and audio production facilities and know of the broad entrenchment of that format into the home environment. Some of us may have experienced systems with higher channel counts. Dolby introduced 7.1 to theaters in 2010, and the following year began private demonstrations of 11.1 systems and then further experimented with additional subwoofers and height channels behind the screen.

They finally determined that a fixed channel count was a dead end and in 2012 they introduced Atmos — a scalable system that can accommodate up to 128 unique simultaneous voices played back through up to 64 speakers, each with its own independent source and amplifier. The speakers are arranged behind the screen, along the side walls (starting very close to the outer edges of the screen), across the rear wall and overhead. All speakers (except subwoofers) are full range and there are additional subwoofers on the rear wall. The total number of speakers is determined by room dimensions.

With this deployment, Atmos claims to deliver accurate and consistent off-screen imaging. The demonstrations we heard seem to support this, and in fact the placement of side speakers very close to the front wall helps to pull front imaging wider. Tom noted that many mixers are already delivering "Wide left" and "Wide right" for music and effects. Mixers also have the ability for a sound to "change" in size. They can place a sound in, say, one speaker overhead and then have it expand outward through adjacent speakers - beware of The Blob!

All installations are done by Dolby, and systems are mapped and tuned using their Lake system. Daily auto-calibration can be handled by the system. To date there are 180 Atmos theaters in North America and over 300 worldwide. The smallest commercial installation is a 40 speaker system.

Atmos sound is delivered to theaters as part of the Digital Cinema Package (DCP) and so can only be used with digital cinema; it cannot be used for traditional film release. Separate files for Atmos & PCM 5.1/7.1 are delivered together in the DCP, and the theater playback system determines which version to access and play.

Approved post facilities will need to be slightly larger, with a 12' minimum distance from mixer to screen and ceilings will need to be higher to allow for the overhead channels. There is currently only one Atmos post facility in New York City with another coming online soon (although Dolby in NYC has a small 16 channel "edit room" upstairs), there are "a few" at Skywalker, and Hollywood has a dozen or so. One goal in the development was to create a system that could easily integrate into existing post production workflow. Mixers can start by creating their 5.1 or 7.1 mixes as they have previously and work with them as placement "beds" which are then modified further to take advantage of the additional discreet speakers. Sources are defined as "objects" which can be directed around the room via Pan-through arrays. Existing 5.1 or 7.1 mixes can be "remixed" in Atmos by converting stems, or going even earlier in the production process and pulling out different elements and making them into objects. New Atmos mixes can also be created from scratch and the Dolby Rendering and Mastering Unit (RMU) can automatically create (with user defined parameters) 5.1 or 7.1 down mixes. Pro Tools 10 offers an Atmos plugin, which includes custom "arcs" for panning objects around the room, and consoles by Neve and Harrison also can be made Atmos compatible.

The meeting concluded with some lively Q & A, but not before we saw (and heard) two more clips, one with a couple of Hobbits in a watery cave and one with some astronauts on a space walk gone bad.

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