Modern movie theaters make it a point to call out screenings offered in 3D, IMAX, or some combination of the two. Then they charge a premium for them, and film fans (us included) gladly shell out for an enhanced viewing experience. (Whether those enhancements are worth the price is a discussion for another day.) There’s a new technology trickling its way into movie houses across the globe, though, that represents another leap forward in cinema viewing — and it’s all about sound. It’s called Dolby Atmos.
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Most movie-watchers (especially cinephiles and audio geeks) should be familiar with Dolby through its multi-channel “surround sound” audio, which envelops viewers in the on-screen action both at local multiplexes and at home. In the most common “5.1” audio setup, the room and the speakers inside it are divided in to five full-bandwidth discrete audio channels plus a restricted-bandwidth sub-bass signal (that’s the “.1″) dubbed the LFE (Low Frequency Effects) channel. The center channel typically handles dialog and other sounds that need to be keyed to the middle of the screen while the left and right front speakers output the stereo elements of the soundtrack. The right and left rear speakers provide two extra channels that can be used to play any other type of audio element that the mix engineer deems fit. 5.1 is a significant leap forward compared to traditional stereo setups for creating a “wrap-around” soundstage — but it’s still a very crude approximation of the infinite number of routes that sounds can take when approaching your ears in everyday life.
Atmos is the next evolutionary step. In a theater setting, the first-generation Dolby Atmos Cinema Processor powering the world’s first wave of Atmos-compatible cinemas can support up to 128 distinct objects (i.e., a specific sound, say, the chirping of a cricket) and/or channels at any one time, which can then be directed across up to 64 unique speaker locations within the theater. How sounds are directed to various speakers is the other half of Atmos’s underlying magic from the standpoint of the sound mixer.
Since the number of speakers and their placement throughout the room can vary from theater to theater, Atmos allows mixers to think in terms of spacial placement versus speaker placement. Inside the theater, Atmos technology then analyzes the audio setup and adjusts the output across the various speakers to best match the “spatial” choices made by the mixer.
“Dolby Atmos provides the completely immersive sound experience that filmmakers like myself have long dreamed about.” – Peter Jackson
The ability to play back a much wider number of individual sounds from exponentially more positions and directions utterly tramples 5.1’s audio track and channel limitations and creates an environment significantly closer to how we hear in the real world.
Think about a helicopter circling overhead in a movie. Instead of hearing the propeller sounds shift from the left front, to left rear, to right rear, to right front corners of a theater in a crude circular pattern, Atmos can allow the same effect to move across each individual speaker surrounding the audience, and can even utilize speakers placed overhead on the ceiling, providing the sense that the helicopter is positioned over the audience’s heads. Beyond adding a new dimension for viewers, the technology gives movie sound designers and mixers a new level of artistic freedom.
Unfortunately, only 101 theaters or so in the U.S. are currently Atmos-compatible. That’s not bad, considering the Dolby Theatre in Hollywood was the first one to open in June 2012 — but it still represents a tiny fraction of the total theaters in the U.S. Dolby hopes to grow that number to at least 1,000 venues globally by the end of 2013.
It will also take time for Hollywood production teams to fully embrace the format’s technology and make the most of it during the production process. Pixar’s Brave was the first to debut in the Atmos format in 2012 with 12 other titles following suit that year. That number will more than triple to 40 titles, and include most of the year’s major blockbusters (where advanced sound mixing is likely to have the biggest impact), by the time 2013 comes to a close.
Our thoughts after watching Danny Boyle’s latest film Trance in Dolby’s own Atmos theater earlier this year? “Hear the whole picture” is is Atmos’s tagline, and it seems entirely pertinent. Consider us convinced: by opening our ears Dolby can open our eyes.