Three spaced mics goes all the way back to the very begining of non-mono electric recording with Harvey Fletcher's experiments for Bell Labs in the 1930's. It's a currently under used technique for our style of recording IMO, and one of my prefered omni techniques. Could be directionals instead of omnis too, more likely to be used in the center if the outside mics are A-B spaced. Also possible that the center mic was actually a stereo mic, then the outside mics can help provide more width, open ambience and low bass than the center coincident stereo mic would get alone.
Such a three channel recording is typically mixed to 2 channel stereo with the center mic panned to the middle, Left mic all the way left and right mic all the way right, and the evel of the center adjusted to taste. If all three channels are recorded and not mixed in the field to a stereo recorder, that gives the taper more control over the sound balance, timbre and stereo image after the fact than simple two-channel stereo. But these days you can also play back a three channel recording without mixing the channels over a Left/Center/Right speaker setup common with home theater setups. That was the prefered way of doing it in the Bell Labs experiments (they didn't consider 2 channels enough, which was all that later stereo LPs could hold, and also pretty much the practical limit of what people could be convinced to buy) which influenced multichannel movie theater sound and eventually home theater. With mutichannel recording and multichannel playback systems becoming comon in the past decade, it's become much easier to play back three channel recordings over three front speakers.. and it can be a really great improvement!
Mixing 3 mics down to 2-channel stereo before recoring was a relatively common technique a few dacades ago for Grateful Dead taping. But that was slightly different in adding a center omni to a pair of closer spaced directional left/right mics (often shotguns) to help extend the bass response of the shotguns and to provide more a more natrual ambient crowd sound. So the reasons for using 3 mics in that situation were somewhat different than a wide spaced 3 mic A-B setup.
Topic: mic array (Read 7110 times)