Surround Sound Recording

Strongly driven by the movie industry's desire for ever more dramatic effects, numerous multi-channel sound systems have been devised that place loudspeakers beside and behind the listener as well as in front.

The aim of surround sound is to create the illusion of being in the centre of the action instead of in front of it. The simplest surround reproduction setup adds to the stereo pair two extra loudspeakers - one just behind and to the left and the other just behind and to the right of the listener.

To record even the most basic surround sound you need four matched microphones. There are many ways of arranging them, some backed by complicated mathematics, but simply placing four closely spaced microphones pointing outwards at 90° to each other gives good results, and has an added advantage that you can optionally pick off four alternative stereo images as well if you wish. But you'll need a four-channel recorder and quad-core cable, and the whole setup adds to the weight you have to carry. Channel balance is also very critical. It's much more difficult to balance in post-production than stereo because every channel has to balance with all the others.

Only DVDs and hybrid SACDs can handle more than two channels, and for now the traditional Red Book CD still dominates the market for audio discs. So it's a moot point whether the extra cost, complexity and weight of surround equipment is worth it for wild soundscape recording, particularly as it's impossible to position yourself behind a surround microphone array - it has no "behind", so the recordist's perennial problem of staying inaudible is much greater. However, spectacular results can be obtained by recording a dawn chorus in quiet woodland with extreme care in four channel surround sound.