On The Horizon: Multi-Dimensional Audio
[In our On The Horizon series, we look at new and upcoming technologies that you might not see for a while (if at all) but are worth keeping an eye on.]
When you watch a movie or listen to music, a lot of work has gone into mixing the various audio elements together into “channels” for a specific number and location of speakers. And for each situation—whether it be two channels (stereo), 5.1 channels (five speakers and a subwoofer), or 7.1 channels (seven speakers and a subwoofer)—a new mix must be created.
SRS Labs thinks that labor-intensive process is so yesterday, and is looking to Multi-Dimensional Audio (MDA) as the future of audio creation—and enjoyment.
The idea behind MDA is switching from a channel-based mentality to an object-based one. As SRS describes it:
In the real world, sound sources emit from objects in three dimensional space and the sound that we perceive does not only come from the originating source. What we hear is a combination of the direct sound from the source and reflections from the environment. Further, real sound is not confined to specific source positions or locations as it is with channel based audio reproduction systems.
The concept is to represent sound sources as objects in space without worrying about how many speakers you have or where those speakers happen to be. In essence, pulling back from the notion of targeting audio and instead simply delivering audio that includes metadata describing positional information. A renderer/player then maps the audio data to your particular configuration on the fly. Thus, a single MDA “package” could serve everything from mobile devices and home theaters to digital movie theaters and theme parks—and be future-proofed for whatever new comes on the scene.
I got an in-person demo Monday in a hotel suite in San Francisco, and it was impressive. I watched the same video clip (see below) five different times, with various configurations of between two and 12 speakers using the same MDA audio rendered in different ways.
While I won’t claim my ears are golden enough to pick out every variation in detail among the different ears-on demos, I can say that even with two speakers, the MDA audio sounded great. In that stereo setup, the helicopter whirring overhead had a “height” to it more than just the physical placement of the speakers. And individual objects—the growing wolves, police sirens, and alarm at the end—somehow sounded like they had more room to be themselves, as it were. In other words, the MDA audio kept everything clear and separate. (In my demos, the render app was running on a PC.)
I also got to experience an interactive use of MDA. I watched part of a recorded college football game, while SRS director of technology, J. Todd Baker, sat next to me with an iPad. On that iPad was a controller app that he used to—with a tap and drag of the finger—move the announcer’s audio to another part of the room, silence the band playing on-field, and activate the spanish language feed.
Why it’s cool
For sound designers and mixers, MDA means the promise of less work—“a mix once, use anywhere” approach. For studios and broadcasters creating audio soundtracks, it means a lot more flexibility, and the potential to use an open system. Unlike other proprietary systems, MDA is also a royalty-free standard, and codec-independent—it can use AAC, Ogg Vorbis, or even codecs like those from DTS and Dolby.
For consumers, it means a potentially more realistic-sounding audio experience regardless of your AV setup.
Where and when you might see it
If SRS is successful, MDA could wind up in game consoles, AV receivers, set-top boxes, cable/satellite feeds, digital movie theaters, amusement parks, iOS and Android smartphones and tablets, computers, and DVDs and Blu-rays, to name a few.
The company is close to delivering an SDK for digital audio workstations and to create the renderer/player needed for a device to process the MDA signal. A streaming SDK will follow as well. And SRS has been talking to cable and satellite operators, sound mixers, and studios about implementing MDA and has, notably, seen a lot of interest from these content creators in the openness of the system. The company expects to see MDA-encoded audio and MDA-enabled products rolling out in the next year. And with the recent announcement that audio giant DTS will acquire SRS Labs by 2013, it looks like SRS will have the clout and reach to make MDA a reality.