BBC is developing 3D radio

Engineers at the BBC are developing new technology to broadcast radio and television programmes with three-dimensional sound.

By Richard Gray, Science Correspondent

Three-dimensional television may only just have arrived, but engineers at the BBC are already working on the next step - 3D radio.

Researchers at the corporation's technology unit, BBC R&D, have been developing acoustics that can trick the listener into believing they are really at events such as concerts with sound coming from every direction - even above and below.

The technology could bring new vigour to the BBC's long-established sound effects department, allowing its experts to fool audiences into hearing an object rising or falling.

The engineers claim that the new technology should allow consumers to receive 3D sound from their existing radio and television speakers.

Frank Melchior, lead technologist for audio with BBC R&D, said: "We want to deliver a new experience to the audience that gives them more immersion and involvement in the content.

"We also have to make sure we are flexible enough in the delivery of this content. It has to sound OK on headphones as well as on speakers."

It is not the first time the BBC has claimed to have made such a breakthrough. Last year, Radio 4's Today programme ran an April Fools' Day demonstration of 3D radio, asking listeners to hold their hands in front of their faces to get the effect.

The joke, as it turns out, was based in fact. A research paper from BBC R&D reveals hopes for 3D audio which will trick the brain into hearing sound from above and below in addition to the left, right, front and back that are usual with existing stereo or surround-sound audio on radio and TV.

Engineers have tested the new technology with recordings of the Last Night of the Proms, a concert by the rock band Elbow, and a radio play of the Wizard of Oz.

Anthony Churnside, who co-authored the BBC R&D research paper, said: "There are a number of ways to create 3D sound. There are psychoacoustic tricks that can make you perceive sound from above and below.

"With the Wizard of Oz we concentrated on a couple of scenes including the tornado when it takes the house away. Suddenly we had mooing cows thrown up into the air, and the wind could be all around you. With 3D sound you have every direction to play with so you can be really quite creative.

"For an orchestra or a live event, the majority of the sounds come from the stage in front of you, but the sense of immersion comes from the sound bouncing off the roof and the walls."

BBC engineers have been testing different technologies including one called ambisonics, in which the audio is recorded using microphones at different locations.

The soundtracks are broadcast simultaneously, with advances in the computational power of hi-fi equipment and televisions allowing the signals to be decoded and configured to suit each listener's speaker set-up.

Mr Churnside said: "The final solution will probably be a hybrid of the technologies so that we can record, produce, broadcast and listen to the audio in the most flexible way."

The 3D audio could eventually help to enhance 3D television broadcasting, which is expected to increase after the first episode of David Attenborough's Kingdom of Plants was broadcast in 3D by Sky earlier this month.