What we've done

Binaural sound technology allows the creation of immersive spatial audio experiences for headphone listeners. This can enhance programmes when listened to on headphones as well as create immersive interactive experiences including in virtual and augmented reality.

We spent several years developing tools for production and delivery of binaural sound, as well as evaluating industry technology. This allowed the BBC to produce a great deal of high quality binaural content. The work was underpinned by study of the perceived quality of binaural technology, development of signal processing algorithms, and analysis of the workflows of our production staff. Binaural has grown in popularity in recent years, particularly as mobile headphone listening has increased. Towards the end of this project, we worked with the BBC Academy to ensure that our production teams are equipment with the knowledge and tools to create high quality binaural audio.

Why it matters

Over the last decade there has been a large growth in the number of people listening to programmes over headphones. This is largely thanks to the arrival of powerful smart phones, fast mobile data networks, and streaming services such as the BBC iPlayer. Currently most audio we hear over headphones is in stereo, the same content that we play over loudspeakers. But listening to stereo programmes over headphones can give a flat impression with sounds coming from inside the head.

Binaural techniques can be used to create a richer sense of space in programme sound, giving a more exciting and immersive listening experience. We are also working on 3D sound for loudspeakers, but binaural technology can bring that kind of experience to listeners' headphones. This can be applied to traditional programme content but also to new interactive content experiences including virtual and augmented reality.

Our goals

Enable the BBC to create world-class binaural content

Evaluate the user experience of binaural sound in broadcasting

Develop technology to deliver binaural sound to our audiences

Open standards that enable binaural broadcasting

Explore the role of sound in new interactive media (VR/AR)

How it works

Binaural techniques simulate the hearing cues created by acoustic interaction between our bodies and the environment around us. Audio signals are filtered to introduce these cues and give the impression that a sound source is located outside of the head at a given location in space. Our hearing system appears to be sensitive to inaccurate cues, it is common for binaural filters to create an unconvincing spatial impression as well as poor sound quality. Every person has an individual pattern of hearing cues that are created by their unique body shape, also these cues change as a listener moves. Natural binaural reverberation is also important for convincing effect. Achieving high quality binaural sound currently requires careful measurement and specialist equipment. To adapt this for broadcasting requires new techniques based on a better understanding of human hearing.

Outcomes

We have now supported the BBC to make well over 100 programmes using binaural sound techniques, across a wide range of genres, for radio and podcasts, television, and in new interactive content.

For several years running we have enabled production of special immersive headphones mixes of the BBC Proms. The 2019 concerts are available in binaural here. This uses a custom live mixing tool that we built.

We have supported the production of several award-winning binaural audio dramas, such as Sky Is Wider (unfortunately, this is no longer available to listen) and iSpy Sound Detective.

We developed the BBC's first public VR experience, The Turning Forest, which won the 2016 TVB Europe award for Achievement in Sound. More recently we collaborated with the BBC's VR Hub to produce the spatial audio mix for the VR experience Nothing to be Written.

We are now helping more teams in the BBC to apply binaural sound in their work and scale up our ability to produce these experiences.

Besides producing content we investigate production techniques and tools for binaural and immersive audio, including evaluating the latest market developments. This ensure that the BBC is at the forefront in terms quality and creativity in this area. This includes research into signal processing fundamentals and perception of immersive audio, as well as working to establish international standards. Such work as recently occurred through the S3A project and collaboration with the University of York's Audio Lab.

If you're interested in working with us then please get in touch.