[. . . ] Allen Avenue, voice (818) 798 9127 New M/S Stereo TECHNOLOGY Pasaden CA 91104 fax (818) 798-2378 MS38 DM Dual Mode, M/S and L/R LINE LEVEL ACTIVE MATRIX MS380 TX Stereo Microphone Preamp with Dual Mode M/S and L/R Active Matrix and MS380 BP Battery Power Supply Developed for stereo broadcasting by Lauridsen of Danish Radio in the late 1950's, MS stereo has rapidly gained favor in Europe as the technique of choice. However it was not until the advent of stereo television broadcasts in the US that this technique started to be widely known here. [. . . ] Widespread international use of the original MS38 provided the user feedback that is incorporated in the new generation of "dual mode" units. New applications such as using the S channel for additional crowd response heard only by the stereo audience are being developed. (The anouncer's microphone is fed to the M channel and the crowd response microphone into the S channel. ) A similar trick can be done with artifical reverb to control the relative reverb balance for the mono and the stereo listeners . The principle of the M/S system is the matrix combining of a forwardfacing microphone (the M, mid, or mono signal) with a laterally-oriented bi-directional microphone (the S, side, or stereo signal). Often these are stereo microphones with remote pattern control of the M channel, for enhanced flexibility. (Figure 1) The M pickup provides the central sound image, and is the discrete monaural signal. Since both respond in different ways to the ambient or reverberant information present, this is the basis for MS stereo's unique ability to properly reducethe ambient component for mono listeners and increase it for the stereo audience. The M and the S signals are combined in a sum-and-difference matrix (M+S and M-S) to produce conventional stereo (Left and Right) signals. This matrixing to stereo can be done either originally or during post production. The versatility of the technique is that the user may adjust the stereo image as needed. By proper placement and selection of the polar pattern of the M microphone, the discrete monaural signal can be optimized. [. . . ] Additional information concerning the M/S stereo technique can be found in the paper: "M-S Stereo: A Powerful Technique for Working In Stereo" published in the J o u r n a l of the Audio Engineering Society, Vol. This paper was is also included in the anthology: "Stereophonic Techniques, " published by the Audio Engineering Society. [. . . ]