MM-3 type acustic mixer has 3 independent tracks, one collective timbre control for low, medium and high tones. Each track has a gain control, an XLR symmetrical microphone socket, and a Big Jack socket to connect the line. The mixer has one Phantom type power supply switch for all the tracks, and the output: a symmetrical microphone output with sensitivity control level and with impedance switch which allows to send the signal on the long distances by using the low impedance output. It is fed by 230V external power supply. The casing is made of an aluminium section covered with grey-coloured powder.