SRS, a company best known for audio processing used to improve the sound of on-board TV speakers — and one that was recently acquired by movie sound bigwig DTS — has been steadily promoting its Multi-Dimensional Audio (MDA) concept over the past two years, demoing the audio creation/distribution platform to movie studios, music labels, and journalists alike. This spring saw the establishment of version 1.0 of the MDA spec, along with the release of MDA Creator, a plug-in designed for a range of popular audio workstations that enables sound mixers to store audio in the MDA format. Now, the company has added the MDA Director app to its list of new things for 2012.
Before I get into Director, I should first explain the basics of MDA and what it offers. According to SRS, MDA is a platform that can be used to“create, maintain and deliver three dimensional positional data with soundtrack elements in a multi-dimensional audio space that includes height, depth and width.” This makes it a sort of PCM-plus: a container that not only stores audio frequency and amplitude information, but also metadata to describe the position of an audio object. The term “object,” holds particular significance within the MDA environment, because each element in a music production or soundtrack — an acoustic guitar, a speeding Harley-Davidson — exist independently in three dimensions, much in the way that sounds in real life emanate from discrete points in 3D space. This differs quite a bit from the traditional audio paradigm, where instrument tracks or soundtrack stems suffer generation loss when a mix is “printed” into a channel-based format, whether 5.1-, 7.1-, or plain old stereo.
SRS maintains that its object-based MDA provides a future-proof strategy for music/movie soundtrack production. That’s because, with each sonic element stored as an object and tagged with spatial data, it’s a snap to render that info on the fly for an 11.1 presentation, a 22.1 presentation, or any other format the future may hold. With channel-based audio, on the other hand, you need to start fresh and produce a new mix — something we’ve seen recently with the creation of new 7.1 soundtracks for Blu-ray from the original 5.1 sound used for movie releases.
The SRS demos I attended this week were similar to the ones the company held during the last CES. Basically, an 11.1 soundtrack created with MDA was first rendered for playback over a 5.1-speaker system, and then “upscaled” using SRS’s proprietary processing for presentation on an 11.1-speaker system. My reaction this time out was similar to the one I had at CES: I found the audio upscaled to 11.1 to have an entirely believable sense of height and depth that was lacking in the 5.1-only presentation. These qualities were apparent in the chop of helicopter blades as the clip’s protaganist was pursued in a dream sequence, as well as in the bleep of an alarm clock as he awakened from his nightmare. In both cases, the sonic detail created an almost physical, in-the-room, sensation.
The same demo incorporated multichannel music, with a recording by a well-known female singer/songwriter (whose name SRS asked me not to divulge for what I suspect are legal reasons) expanded out to 11.1. The extra height and surround information gave the music a lifelike sense of “largeness” that wasn’t at all artificial; in fact, when things switched back over to plain old 5.1, the sound seemed comparatively flat.
Circling back to MDA Director, that’s the name of an app the company debuted at the recent NAB show that enables the creation of audio objects you can physically interact with on an iPad. In SRS’s demo, audio for a football game could be altered by the viewer to raise the crowd volume and steer its position, mute the announcer’s voice and switch languages, and also move the listening perspective to various points within the stadium. According to SRS’s Alan Kraemer, MDA Director makes audio a “lean-forward” experience by giving the user physical control over various aspects of the presentation.
In a world where audio tends to take a backseat to video, that could very well end up being a killer app.
Al Griffin is the technical editor of Sound+Vision. When not testing TVs and other stuff, he can sometimes be found at his local multiplex.
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