- Parent Category: News
- Category: Technology News
- Published on Tuesday, 11 June 2013 16:24
- Written by Gordon Meyer
It can take a while for new technologies to become the norm in the global film marketplace. Take multichannel sound, for example. While many people think that stereophonic sound didn’t exist in movies until the release of Star Wars in 1977, the truth is it’s been around since RCA and Walt Disney Productions invented Fantasound for the 1940 roadshow release of Fantasia. In 1975, Dolby introduced the technology of four-channel sound (for left, center, right and surround) on an optical soundtrack for the movie Lisztomania, and branded it as “Dolby Stereo” a year later with A Star Is Born. But even after Star Wars’ tremendous success motivated exhibitors to invest in Dolby Stereo equipment, it still took several years before stereo mixes became standard. Since the introduction of Dolby Stereo, there have been a number of advances in cinema sound to lead us to the current standard of 5.1 channel audio, which is usually presented via sound processors from Dolby, DTS or Sony.
In 2012, Dolby introduced its newest audio technology Dolby Atmos with the premiere of the Disney/Pixar film Brave. At the time, only a handful of screens wereequipped to run Dolby Atmos, including Disney’s El Capitan Theatre and the newly re-christened Dolby Theatre in Hollywood. Since then, a dozen movies were released in Dolby Atmos in 2012 and at least twice that many in 2013, bringing the total number of Dolby Atmos films to over 40 titles by the end of this year, including the recently released Iron Man 3 and Star Trek: Into Darkness. Other upcoming Dolby Atmos features include Man of Steel, Monsters University and The Wolverine.
But what exactly is Dolby Atmos, and why is Dolby investing so much to make it the industry’s next audio standard? Stuart Bowling, Dolby’s senior worldwide technical marketing manager, says that Dolby has received a lot of feedback over the years from the film industry’s t top audio engineers about the limitations of Dolby 5.1. “Digital cinema allows for the use of up to 16 channels,” Bowling explains. “When we first started, we were thinking in terms of channels.” Bowling and his colleagues have since learned that professionals like Sound Designer/Mixer Gary Rydstrom want better directionality and full-range surround speakers. “Gary wanted to be able to position sound in the middle and to the side of the audience, but also be able to have something come through the room and not necessarily be able to touch the sides or the back,” Bowling notes. To achieve this result, Bowling and his team took select 5.1 content and re-mapped it into an 11.1 matrix, which included overhead speakers. “It wasn’t perfect, but it gave you the idea of what potentially could happen,” says Bowling. And after private discussions and demonstrations with audio experts and exhibition executives, there was sufficient interest for Bowling to develop this next-generation technology.
Continuing with an 11.1 format as a foundation, the team remixed sequences from the Disney/Pixar film The Incredibles as a test. While the 11.1 mix added benefits, there were some issues. “It was incredibly difficult to mix because we didn’t have the tools to fluidly move sound from the screen to the overheads and back down into the regular surround array,” Bowling explains. In addition to this challenge, the creative community felt the move to 11.1 felt incremental, like the move from 5.1 to 7.1. They wanted a bigger, more dramatic leap, similar to the move from analog to digital or standard-definition video to high-def.
There was also another issue that Dolby planned to address. With the current state of cinema sound, different digital prints need to be delivered to local cinemas, depending on whether the auditorium is equipped for 7.1 or 5.1 sound. If Dolby were to introduce 11.1 or 13.1 technology, this would add yet another DCP specific to the mix. “Here we are in a digital world, and we had more technology in our home in that you pop in a Blu-ray which tells the player, ‘You are in Dolby TrueHD and I will play this back,’” says Bowling. “But in digital cinema, there is no flagging or metadata to enable that kind of automatic switching. We wanted something that would play in any environment. Staying in the channel world wasn’t going to help that.” The decision was made to go back to the drawing board and take into account the entire cinematic ecosystem. The team now created tools that would integrate with existing mixing technologies, like AMS Neve and Avid/Euphonix, because it’s important to make it as easy as possible for sound mixers to continue to work with the hardware they already know. “We couldn’t introduce anything alien because then we’d get resistance,” adds Bowling.
The Dolby team decided to take an object-based approach to sound design, rather than the traditional channel-based approach that has been in place since the 1950s. With object-based mixing, you can mix and combine individual sound elements with the ability to position a single sound down to a specific speaker or group of speakers. To ease sound mixers into using a new system, Dolby Atmos was designed as a hybrid that enables mixers to use a 5.1 and 7.1 bed of channels in mixes or primarily use objects. The object-based approach lets audio designers more accurately replicate sound movement virtually anywhere in an auditorium. This is in contrast to the current technology, where sound shifts from zone to zone with each zone corresponding to one of five or seven channels. For example, in the iconic opening shot of Star Wars, a space ship flies overhead to the foreground followed by a giant star destroyer. With 1977 technology, audio mixers could make the ships’ sound fade from the monophonic surround channel to the center front channel. Using today’s Dolby Atmos object-based approach, the sound would move across a series of overhead speakers so it would move smoothly from the back of the auditorium to the front for a much more realistic and immersive audience experience. A key part of what Dolby Atmos does is to record X, Y and Z axes during the mixing process to create a three-dimensional spatial audio experience.
Auditorium sizes vary from under 100 seats to several thousand, and the variety creates challenges for accurately re-creating a filmmaker’s intent when it comes to precise sound imaging. Dolby’s engineers designed Dolby Atmos to be fully scalable, almost like an audio PDF file. “If you take a photograph that’s a bitmap file and want to make it bigger, that file is going to distort and you’re going to lose resolution,” Bowling explains. “If you squeeze it down beyond its original capture, again, the picture no longer begins to look the same. With a PDF, I can make it as big or small as I want, yet the original intent of that PDF is preserved.” Dolby Atmos uses this concept of scalability for audio information. “So now I can make the sound as big as I want or as small, depending on the room size, but all the information is there,” says Bowling. “I’m not losing anything and I’m not seeing any degradation.” So far, the industry and exhibitor response to Dolby Atmos has been positive, but, because of time constraints, most of the recent movies released in Dolby Atmos were originally designed from the standard 5.1 and 7.1 channel mixes. Audio engineers worked with pre-mix sound elements to reposition certain sounds to create a Dolby Atmos version. “There are certain restraints there because those sound elements were created differently in the beginning,” says Bowling. “We can go much further when the movie was created naturally in Dolby Atmos.”
Just as cinemas need to be retrofitted with the Dolby Atmos Cinema Processor CP850 and additional speakers in order to run Dolby Atmos, mixing stages also need to be upgraded. Dolby has worked closely with AMS Neve, Avid and Harrison Consoles to develop plug-ins for Dolby DFC. Pro Tools and the IKIS Automation Engine will ease mixers into creating a Dolby Atmos mix by using modified versions of the tools that are familiar. In addition to the plug-ins, mixing studios will also install speakers and a Dolby Rendering and Mastering Unit (a studio version of the Dolby Atmos Cinema Processor CP850) so mixers can hear the full audio dimensionality that they’re creating.
Like with any other new technology, sound designers will encounter a creative learning curve as they figure out how to effectively incorporate this added audio dimensionality to enhance storytelling, just as earlier artists learned to use color, stereophonic sound and 5.1 channel sound technologies as genuine storytelling enhancements instead of as audio gimmicks. Meanwhile, Dolby continues to move forward with its Dolby Atmos deployment. As of press time, Dolby plans to have approximately 100 screens equipped with Dolby Atmos in the U.S. by the time Man of Steel opens on June 14. And with another dozen Dolby Atmos films slated for release between now and January, it’s reasonable to project that number to increase significantly. But the real test will be with audiences as more and more films with native Dolby Atmos mixes truly showcase the technology. Stay tuned.