M-S Stereo

Abbreviation for Mid-Side, a method of stereo miking and recording. MS recordings capture the relative intensity of different sounds across the stereo soundfield. In order to make an M-S recording one must deploy a cardioid pattern mic facing the sound source(s) and a figure 8 pattern positioned sideways to the source. The figure 8 mic is connected to two channels of the mixer, with one channel having its polarity reversed. Each of the two signals (one of which is polarity reversed) of the figure 8 mic, when combined with the signal from the cardioid mic produces either a left or right “image” that is roughly equivalent to two cardioid mics positioned with a 90 degree angle between them. The only advantage to the MS method is the user can alter the width of the stereo image by varying the relative levels of the two microphones. There are several disadvantages, most of which are a function of having two dissimilar mics reproducing the same signal. Of course they can’t occupy the exact same space either, which produces other phase and frequency response anomalies.