Dolby Atmos – a visit to Dolby’s new screening room in SohoJanuary 30, 2013
Last week I had an opportunity to visit Dolby Labs new London home in Soho Square, the trip was mainly to visit one of our students from one of our audio engineering programmes at Salford University who is on placement there for 12 months. The screening room here is impressive in itself – a small cinema with near-perfect acoustics and a 4K projector, pretty much an ideal listening environment and as part of the visit I got to experience Dolby’s Atmos demos. I’ve been looking forward to this for quite a while…
Atmos is an exciting prospect for many of us involved in audio research as it is the first commercial object based audio system that has potential to go mainstream. Object based audio is a big leap forward from the channel based systems we are used to. In channel based audio – such as two channel stereo, 5.1, 7.1, 9.1 etc – the production (or the recording) is tailored for a specific loudspeaker configuration – this sound goes to this loudspeaker, this one goes between these two etc. In object based systems however each audio object, each sound, is defined not by its relationship to the loudspeakers and their placement but by a 3D coordinate location. In principal this means you can define your audio objects in production and render them across a wide variety of loudspeaker configurations, everything from conventional 5.1 and 7.1 to more immersive systems with a height component provided by loudspeakers above your head.
The full Atmos system uses up to 64 loudspeaker tracks, there are speakers along the side walls of the room, behind you, a pair of subs for low frequency content suspended from the ceiling, 5 loudspeakers behind the screen (left, centre, right, left centre, right centre) and two rows of speakers running along the ceiling from the rear of the theatre to the screen. The basis of the mix is a 9.1 bed – so still familiar territory to sound engineers and mixers everywhere – but in addition there are up to 128 active audio objects which can be flown anywhere around the speaker setup and are added on top of this 9.1 bed. One of the drivers here is a produce-once-play-anywhere approach. It has parallels with the work we’ve been doing on the FascinatE research project where we are also working with object based audio but in the context of live event broadcast rather than movie production. Like in FascinatE (which I have written about before) each audio object has its own metadata that tells the system where to put it and how to manage it in different reproduction environments.
You can see a short video I shot with my mobile of the back end of the system in the projection room here, there are meters for the 9.1 bed and a 3D representation of the cinema – the yellow circles are audio objects, many of which are animated. Please excuse the poor video quality but I think it gives a nice overview of the Atmos interface.
The possibility of avoiding having to make separate mixes for each reproduction system makes good commercial sense but it is the listening experience that impresses me most. Action scenes were rendered much more exciting and immersive and had a ‘WOW’ factor but the real power in the system is in more subtle application which, for me at least, places you inside the scene much more effectively than 3D video content ever has. A clip of The Woman in Black in particular (mixed for Atmos by Ian Tapp) was startling and quite unnerving with floorboards creaking overhead and the voice of a ghost coming from the rear of the cinema. Very very impressive indeed and I’m holding out on seeing The Hobbit until I can see it in Atmos. Sadly only one UK cinema has the system installed so far though, I suspect this may change.
Many thanks to the terrific folk at Dolby for running these great demos for me.