Topic summary
Stereo field
Extracted from the Wikipedia article Stereophonic sound.
M/S technique: mid/side stereophony
The left and right channels are produced through a simple matrix: left = mid + side; right = mid − side (using a polarity-reversed version of the side signal). This configuration produces a completely mono-compatible signal and, if the mid and side signals are recorded (rather than the matrixed left and right), the stereo width can be manipulated after the recording has taken place by adjusting the magnitude of the side signal (a greater amplitude giving a greater perceived stereo field which can be made to exceed the distance between loudspeakers). This makes it especially useful for film-based projects.