The scariest part of a mortar round isn't just the fact that it can rend your limbs off with consummate ease. A sniper interdicted with mortar fire knows the morale-breaking potential of an incoming shell's tell-tale banshee wail. It's the same case with the massive boom of an MOAB bomb, the terrifying crack and bang of a supersonic MLRS rocket's top-down attack, or the blood-curdling scream of a Junkers dive bomber as it swoops down for the kill. If you haven't clued in on it yet, the military has been raining death from above and has leveraged the psychological impact of war sounds to cripple enemy morale for a long time now.
However, according to Dolby Labs, Hollywood hasn't been able to reproduce the full extent of this aural terror in cinemas yet. The argument being traditional theatre sound systems can only pan audio across the horizontal plane. This lack of height in the sound stage cannot produce the sort of three-dimensionality required to enable true vertical panning. The solution, if recent trends are to be believed, is an array of speakers along the ceiling that's touted to envelope listeners in a bubble; thereby allowing sound effects to be positioned in full 3D glory.
With the stereoscopic 3D craze currently sweeping across the cinema and home video segments, it wasn't long before the prefix was applied to the audio component as well, especially after many decades of dalliance with the visual one. Dolby likes to call it Atmos—its spanking new proprietary cinema sound system that employs up to 64 speakers along the front, rear, sides and the ceiling inside the theatre in order to envelope listeners in a dome of sound.
Dolby Atmos: the closest you'll get to being trampled by horses without being, well, trampled by horses
It blends the old with the new thanks to its combination of existing static channel-based approach and a dynamic object-based system. The 3D audio setup can feed up to 64 separate speakers with a total of 128 uncompressed audio inputs comprising of channels and objects. The first of its two-pronged sound spatialisation approach assigns ambient sounds that don't require much steering to discrete front, rear, and side channels.
The real magic, so to speak, manifests in the way the Dolby Atmos decoder/processor maps dynamic objects to each discrete speaker. These objects are essentially sounds coupled with metadata that allows the audio processor to compute and assign a panning trajectory on-the-fly, which is then used to move these sounds through the speaker array. This implementation is vastly different from the existing methods of multi-channel steering in which sounds are rigidly assigned to channels in a pre-determined manner.
Dolby's dynamic approach is best illustrated by considering the object as a helicopter. At the post production stage, the mixing engineer essentially pairs the sound with metadata that tells the Atmos audio processor what sort of trajectory the helicopter should follow along the theatre. The hardware then procedurally maps the object to each speaker and thereby steers the helicopter over the audience, just like the sound engineer had intended.
The only place where you'll find more speakers is at the Dolby Atmos factory
This is a more elegant approach to sound spatialisation because, in this case, the panning doesn't take a rigid, predetermined route. It is instead implemented using an algorithm that allows the same audio mix to be used for theatres of different sizes and number of speakers. This is vastly better than existing multichannel setups that call for separate audio mixes for different speaker configurations. Interestingly, video games have always incorporated a more sophisticated version of Dolby Atmos' procedural sound mapping (ignoring the vertical panning aspect, that is) since the 90s with advanced procedural 3D sound APIs such as Open AL, DirectSound3D, Aureal A3D, FMOD and Miles Sound System.
All this seems good on paper, but does it really make a profound enough difference in practice? To find out, I visited Sathyam Cinemas Complex in Chennai—home to India's only Dolby Atmos installation. Costing about Rs 20 lakh per screen, the Atmos installation had transformed the multiplex's Serene screen into an orgy of speakers. Every surface you could lay your eyes upon (except the floor, of course) was peppered with imposing cinema-grade drivers, replete with huge trusses on the ceiling supporting three rows of ceiling-mounted speakers.
The theatre had been treated with a sound-dampening material, which Senthil Kumar of Real Image Media Technologies revealed was meant to attenuate reflected sound. This is crucial because unlike regular theatre sound systems, Atmos generates sound reflections artificially instead of relying upon natural harmonics of the cinema hall. Since everybody and their uncle loves bass, he didn't hesitate to underscore the fact that Dolby's 3D sound system also incorporates additional LFE (subwoofer) channels for an even more impressive low end impact.
Brave was the first movie to get the Atmos treatment
The result was hard to ignore when the setup was put through the paces with a barrage of audio samples showcasing its 3D panning capability. While bullets and arrows whizzing past are rendered convincingly by regular 5.1 systems, they simply can't pan overhead objects such as helicopters anywhere nearly as convincingly as Atmos. The virtual chopper hovered over our heads with such realism and pinpoint positional accuracy that it beggared belief.
This was followed up with an audio-only simulation of thundershowers, which turned out to be even more impressive. I have auditioned similar audio samples on 5.1 and 7.1 systems, but having an array of speakers overhead makes a marked difference. To put it in a nutshell, I could almost instinctively feel myself cringing and bracing up for the cold, fat drops of rain. I don't mean to exaggerate, but it indeed was very close to actually being there.
What good is a trip to Chennai without homage to Rajinikanth? Well, the city's oldest film production house AVM Production showcased the 3D version of Sivaji – The Boss, which had been given the Dolby Atmos as well as stereoscopic 3D treatment. I wish I could have reported where the first Indian Atmos-pimped movie stood with respect to its rehashed 3D sound, but the decibel levels for the two songs and one fight sequence showcased were so chronically high that I'm afraid I may have suffered permanent hearing damage. Then again, it's only appropriate for a Rajini film to make your ears bleed. Maybe someday I'll be man enough to sit through the aural agony of that sort.
The place where it all begun
Next up was typical Hollywood fare that seemed like a walk in the park in comparison. Although the demo from Chasing Mavericks exaggerated the 3D sound effects a bit, it thankfully had no intention of destroying my eardrums. The sheer scope and scale of monstrous waves, as experienced from classic POV setup once again underscored the importance of Dolby's positional audio.
Then again, all these were short clips of the juiciest film sequences. The recent Atmos title Life of Pi, however, was an exercise in subtlety. Much like its sensible implementation of stereoscopic 3D, the sound design was equally restrained. It never really tried too hard to pimp up every scene with positional audio, but when it did (like with the storm sequence), the results were spectacular.
In the simplest of terms, an investment of Rs 20-30 lakh isn't a significant amount for multiplexes, but the difference in the overall aural experience is well worth it. If we're dealing with action movies, I wouldn't mind paying a bit extra for a Dolby Atmos-enabled movie. Unfortunately for Dolby, things won't necessarily be as straightforward and easy in the near future.
The One Ring, and way too many speakers
Interestingly, despite judiciously dropping the word revolutionary in its PR blitz, Dolby's Atmos is more evolutionary than a true pioneer of 3D sound. There already are other players in 3D cinema sound segment, which have deployable implementations of their proprietary 3D audio solutions. These include players such as Barco-backed Auro-3D, Immsound, Illusonic 3D and Iosono, which packs in a whopping 180 speakers. Auro-3D especially was launched last year and enjoys a head start, and it's backed by Dreamworks Animation as well.
Earlier this year, it had beaten Dolby's Atmos to the punch, as the same Chennai-based Sathyam Cinemas played host to Kamal Haasan's Auro-3D powered trailer launch for Vishwaroopam. Meanwhile, Haasan seems confident of having at least 30 theatres across Tamil Nadu and Kerala outfitted with Auro-3D capability in time for the January 2013 launch of the movie. On a lighter note, Pankaj Kedia, the Country Manager for Dolby Labs India made it a point to quote George Lucas during the Atmos press conference. This is especially magnanimous of him considering the fact that Lucas and his studio have embraced rival Auro-3D instead. At the end of the day though, let's not forget that the Dolby brand has a much better recall value and pull over its competitor.