Engineers at BBC Radio 3 have been busily working on a rediscovered 1958 recording of Nine Lessons and Carols from King's College Cambridge, but rather than the relatively simple audio restoration that normally goes into these projects, the team decided to try something a little more ambitious. Although the original recording was only stereo, the team has been able to use computer processing techniques to create a quadrophonic (or four channel) surround mix, putting it alongside a true 4.0 recording from 2007 for comparison.
To enjoy it, you'll need a surround sound setup mapped to the four channels, and some free software (available for Windows only) that's capable of playing back the recording. However, there's also a binaural mix (where two channels are engineered to sound like surround) of the 2007 service that anyone can try, and all you'll need is a good pair of headphones. Head over to the BBC Blog for the story behind the recordings and listening instructions.