[Wired]

BBC R&D’s audio team is looking at potential next generation audio formats. It already outputs mono, stereo and 5.1 surround sound, but the organisation is keen to investigate 3D sound.

Ambisonics — which refers to truly three-dimensional sound — is an area of particular interest. Ambisonics is different from other surround sound formats, such as 5.1 because it doesn’t rely on a specific speaker layout. Ambisonics captures the entire 3D sound field as a set of spherical harmonics which can then be decoded for a wide variety of speaker layouts, including stereo and 5.1. This means the audience can pick the sound profile that best suits their listening environment.

Ambisonic systems have traditionally been too expensive to explore, but the combination of increased computing power and diminishing hardware costs means that it is now a viable solution. The team experimented with ambisonics at an Elbow gig in Manchester Cathedral. The BBC R&D audio team captured a full sound scene using a combination of ambisonics and close microphone techniques. This helped the team to understand the challenges of integrating 3D audio capture and mixing into real-world live production environment.

They play their recordings back in a dedicated listening lab featuring a 16-speaker set up. Given that it’s not too practical to require an entire room filled with speakers in order to listen to the results, they used binaural reproduction — using a system developed by Smyth Research called a Realiser — to simulate surround sound over headphones. The system needs to be configured for each individual’s head shape and ear position and then tracks the movement of the head in order to ensure the sound comes from the right place. Wired.co.uk tried a pair that were configured for someone else’s head and ears, but the results were still impressive, particularly with the reverberation from the Cathedral.

The Beeb team — based at the North Lab in Manchester — even developed its own spatial audio panner which uses gestural control to move sound around a 3D space. Audio Research Engineer Chris Pike explains: “Traditional mixing desk have a single rotary controller which controls the panning for each channel. When you have control over sounds in 3D space it becomes much more complex.” Using a Microsoft Kinect as the gestural controller, the team can pick up and move sounds around the 3D scene in real time using arm movements. We can only assume Imogen Heap will be impressed.

See the original story and watch the video here: http://www.wired.co.uk/news/archive/2011-12/16/bbc-audio-innovation