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AES Section Meeting Reports

Los Angeles - June 25, 2013

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Summary

The June 2013 edition of the monthly meeting saw the Los Angeles Section pack things up and head for Burbank to pay
a visit to Dolby's Larry Umlang Theater. Guided by senior product manager David Gould, the meeting had one focus:
Dolby Atmos. Kicking things off with a brief overview of the new immersive sound format unveiled last year, Gould
moved on to present several film clips illustrating its potential before fielding questions from the audience- all in a room in
which actual Atmos film mixes had been auditioned and the technology itself developed.
As Gould explained, following somewhere between twelve to eighteen months of development time, Atmos made its film
debut in Pixar's 2012 release, Brave. In terms of speakers, Atmos's most dramatic offering is the addition of overhead
arrays. This augmentation allows for more fluid movement, especially when the intention is to send something over the
audience's heads via the ability to pan through the arrays rather than simply jump between surrounds (potentially from
one side of a room to another). Additional speakers in the front of the room provide the opportunity to expand the perceived
soundstage. For example the score could be pushed wide to free up room to further flesh out dialogue or other on
screen content.
To speak only of the number of speakers involved and their placement, however, is to largely miss the essence of what
Atmos brings to both theaters and studios. At its core, Atmos is about a move away from channel based mixing towards
what Dolby technologist Stuart Bowling terms audio objects. While Atmos mixes include a 9.1 channel based 'bed' mix,
they also feature up to 118 audio objects. The audio object concept is as follows- instead of assigning a particular sound
to a channel or channels, the mixer assigns the sound to a point in space.
That's literally a coordinate in 3d space, so regardless of the speaker configuration the object will be placed in it's
intended position by the rendering unit required for Atmos playback, Dolby's CP850 Cinema Processor.

Given a room's
dimensions and a bit of information about the playback system involved, mixes for any environment and configuration
can be generated from the original Atmos mix. The positioning is implemented through metadata, and mixers specify
placement via a ProTools plugin which then communicates with the CP850.
Having established the basics of Atmos, Gould presented a sequence of demonstration material, including scenes from
Star Trek: Into Darkness, The Hobbit: An Unexpected Journey, The Woman In Black, and Life of Pi. Each represented a
somewhat different application of the technology. While the Star Trek clip went to show how the technology can handle
sweeping action sequences, the other clips elucidated more nuanced uses. For example the reverberant, Gollum
inhabited cave settings of The Hobbit benefited from the inclusion of overhead speakers in creating a sense of
immersion, even disorientation, while The Woman in Black's creaks and rustles were placed precisely throughout the
theater, heightening the suspense. As Gould explained, Atmos not only creates finer control and resolution for
movement, but also for pinpoint location of individual sounds.
In the case of Life of Pi the audience had the opportunity to hear an example of the audio objects separated
from the rest of the mix. A scene featuring a school of flying fish provided much to work with in terms of discrete object
selection, especially when many of the fish landed on the deck of Pi's boat.
To put things in perspective with respect to Atmos's standing in the progression from mono to today's audio formats,
Gould mentioned that while 5.1's first year yielded about 20 releases employing the then new technology, over 50
titles with an Atmos mix reached theaters within the first year of its release. In the Atmos case, each of the major studios
contributed to that overall total. At present, roughly 200 theaters worldwide have implemented some form of Atmos.
The meeting concluded with a question and answer session which brought to light, among other things, whether
there are plans to float theater floors and install speakers beneath your feet (the answer is no) and the issue of loudness.
Each of the speakers included in the new overhead arrays, as well as any additional surrounds, are capable of full
range output. In some cases this would imply upwards of 30 speakers each capable of sending 105 dBSPL into a room
simultaneously. While Gould acknowledged this possibility he estimated it's likelihood at very low to none.
He went on to add that regardless of the audio format in use, with respect to volume levels Dolby and other audio
format purveyors find themselves in the middle of a tug of war between theaters and studios. While mixers want audiences
to experience the full dynamic range of their work, oftentimes theaters will set volumes lower, which in turn
leads to louder mixes being delivered: a decibel arms race. How Atmos may fit into the situation remains to be seen, but
in the mean time both sides seem to be warming to Dolby's immersive new format.

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