Those fortunate enough to see the Oscar-winner ‘Gravity’ in 3D in their local cinemas would have marvelled at the technical wizardry of the 3D visuals in front of them. What they may have been less aware of was the importance that the sound mix played in this spectacle. In fact, unless they were lucky enough to watch ‘Gravity’ in one of the 300 cinemas that house the Dolby Atmos sound system, they would not have experienced ‘Gravity’ in all its audio glory.
So what was different about the sound in ‘Gravity’? Originally, the film was mixed in 7.1. However, it was then remixed as a Dolby Atmos mix, which was launched in 2012. Dolby Atmos uses speakers placed all around the cinema, including the ceiling, with the sound designers having mapped the direction of the sounds, so they move physically throughout the theatre to match what is happening on the screen. The effect of this is to have waves of audio coming out to parallel the 3D visuals that you are experiencing on screen. A film like ‘Gravity’ showcased this system perfectly, with the dialogue and action whizzing round the speakers in a 360 degree cyclone.
This new Dolby Atmos has revolutionised 3D sound and moves beyond the parameters of 5.1 and 7.1 mixes to really bring 3D visuals to life. Although not the first film to be mixed for Dolby Atmos, (‘Brave 2012’ was released with a Dolby Atmos sound mix) it is the first film to win the Oscar for the Dolby Atmos sound mix, really raising the profile.
Another method of delivering 3D sound into movie theatres is by binaural sound. Binaural sound can only be experienced by wearing headphones, as it represents a true reflection of the audio as if you were actually in the room with the actors. Binaural sound has on-set production implications, as well as practical implications of introducing it into cinemas. For instance, to record binaural sound you typically attach two microphones where each ear is on either side of mannequin head, which is placed to reflect the position of the camera’s vision. What this does is record accurately the sound in the room to reflect distance and movement of the subjects. The problem with this is that sound recordists on set bust a gut to record good clean dialogue so the audience can follow the story. Now, the dialogue you hear on a film is not typically accurate volume-wise to the distance of the actor away from the camera, but it is an accepted white lie which enables the audience to actually hear what is happening without having to try to hard, thus bringing them out of the engineered construction of the story.
A binaural sound recording would not deliver such clean audio, as when the actor moves away the dialogue would become quieter and potentially be lost. Binaural sound also has production implications on set. For example, many sets are constructed and are actually ‘half’ a world, i.e., the half we can see. A binaural sound recording would have to reflect what was happening on either side of the framed image and the implications of that would be constructing bigger sets to encompass everything you may hear in that environment. This would have production cost implications.
In addition to these other issues, headphones would have to be worn in cinemas, detracting from one of the pleasures of going to the cinema - feeling part of an audience. There would be no feeling of shared experience, which is significant. Having said that, you would also not have to ‘share’ the experience of somebody noisily eating his or her popcorn. There is also the issue of the musical score. It would not sit comfortably onto top of this distance relative soundscape and would seem jarring, I feel. However, nonetheless, it can be effective when used properly.
Moving forward, it would seem that ‘Gravity’ has rubber-stamped the success of the Dolby Atmos mix, and will hopefully pave the way for more cinemas installing this sound system, to enhance the growing number of 3D movies hitting our cinema screens. I for one can’t wait. To follow the growth of 3D film developments go to @3DtheFuture on twitter!