MTX 191 A
The MTX 191 A matrix amplifier is used for processing the MS microphone signals of the RSM 191 shotgun stereo microphone, or the active capsules AK 20 and AK 40. The level of the side signal is variable, independent of which output mode is selected (MS or XY). It is adjusted through a rotary switch in 3 dB steps from -9 dB to +6 dB, relative to the level of the middle signal. Consequently the pickup angle is varied in steps between 60° and 170°.
Depending on the position of the rotary switch on the front of the matrix amplifier the output provides either an MS- or XY-signal. The XY-signal is obtained from the MS-signal by summation (X = M + S) or subtraction (Y = M - S). In both modes an electric left-right-inversion is alternatively possible if during the recording the microphone is turned upside-down.
To suppress low frequent interfering noise the matrix amplifier has a switchable high-pass filter at 40(LIN)/80/200 Hz. The power for both matrix amplifier and microphone, is either supplied by a 9 V battery (IEC 6 F 22), or through external 48 V phantom powering.
The RSM 191 is connected with the 7-pin KT 5/KT 6 cables. Two AK... active capsules can be connected with an AC 30 cable. The audio is passed through a XLR 5 M connector. The output signal is DC-free. Use AC ... adapter cables to connect the audio to unbalanced inputs.