M-S (Mid-Side)
– A specialist form of coincident microphone array which, when decoded to left-right stereo, creates an equivalent XY configuration. In the MS array one microphone is pointed directly forward (Mid) while the second is arranged at 90 degrees to point sideways (Side). The Mid microphone can employ any desired polar pattern, the choice strongly influencing the decoded stereo acceptance angle. The Side microphone must have a figure-eight response and be aligned such that the lobe with the same polarity as the Mid microphone faces towards the left of the sound stage. Adjusting the relative sensitivity of the Mid and Side microphones affects the decoded stereo acceptance angle and the polar patterns of the equivalent XY microphones.