BBC Radio trials 'surround sound' broadcast technology

BBC Radio has launched a technology experiment that offers surround sound through standard headphones, starting with a Christmas service from the BBC archives.

From today, listeners can access an experimental stereo recording of the 1958 Festival of Nine Lessons and Carols from King's College, Cambridge. The trial also includes a re-production of the recording made by the BBC in 2007 using '4.0' surround sound.

The broadcast, which is available now online, uses a 'binaural' format, which creates realistic and immersive depth that mimics surround sound through ordinary headphones.

Listeners can plug their headphones into any computer with a stereo output and then stream the specially-processed audio recording. The BBC said that this should "make them feel as if they are hearing the music from speakers around them, not just their headphones".

There are six different sound settings to choose from, depending on the user's headphones and head shape.

The surround sound trial is part of the BBC's innovation with audio technology, including the launch of HD Sound and the ongoing trials with '3D Sound'. BBC Radio 4 will broadcast live coverage of this year's Nine Lessons and Carols on Christmas Eve in HD Sound.

BBC director of audio and music Tim Davie said that the experiment could lead to the BBC offering surround sound on future radio broadcasts.

"We have stepped up our innovation within the BBC so that listeners can enjoy an even better experience of radio," he said.

"If successful, our intention is to offer surround sound on a whole range of BBC programmes. This is part of an exciting series of trials such as HD Sound, and personal control of crowd versus commentary audio during events such as Wimbledon."

BBC audio and music head of technology Rupert Brun added: "This experiment is an attempt to enhance the standard 'stereo' sound headphone users have had for over 50 years and, although it is only a trial at this stage, if listener feedback is positive it could offer a significant improvement to audio quality in the future."

The festival was selected because King's College Cambridge has "a rich reverberant acoustic and the location of choir, organ and congregation offers good opportunities for surround sound", said the BBC.

Both the original experimental recording of the festival and the 2007 re-recording in 4.0 surround sound are available online and can be enjoyed through a home cinema system. The 1958 stereo recording has been converted to surround sound using technology from Fraunhofer IIS in Germany.

Anyone wishing to listen to the broadcast via loudspeakers will need to download a Fraunhofer IIS player to their computer. Currently, this only available on Windows, and not Mac.

Fraunhofer IIS head of department multimedia realtime systems Harald Popp said: "We are glad to support the BBC's efforts through underlying technologies such as the MPEG Surround audio codec, that allow the creation and delivery of natural surround mixes from original stereo or surround recordings. The multi-channel audio stream is encoded in the most efficient way, backward compatible to stereo players."

Watch a video presented by the BBC's Anthony Churnside on how binaural files are produced: