The MM12 is a highly flexible twelve input, twelve output 144 cross-point matrix unit. Any number of inputs may be selected to any number of outputs using the front panel DIP switch matrix. The switches are large so the on/off status of each cross-point is easily visible. All inputs and outputs may have up to 12dB gain with an additional 10dB gain available on input switches and output presets making a total of 46dB of gain available. LEDS on both inputs and outputs illuminate green if a signal is present on the input or output or red if an input or output is clipping. All system inputs and outputs are on standard XLR connectors.
Matrix cross-points are available on front panel DIP switches. Inputs are organised as horizontal rows and outputs as vertical rows making cross-point status easily visible. To select an input to an output just slide the appropriate DIP switch to the right.
Matrix inputs are active and have an input impedance of 10k ohms. The level controls on the matrix inputs allow a gain range of off to +12dB if the three position toggle switch is set to centre position (0). With these settings the input will be at unity gain if the input level control is also set to vertical (0).
With the toggle switch set to +10dB the gain range is off to +22dB with +12dB gain when the input level control is vertical (0).
The toggle switch also has an off position which is useful for temporarily cutting an audio input while still retaining that channel's gain setting.
The input channel LED will illuminate green is the input level is over a preset threshold. This threshold may be adjusted for all input channels using the Input LED threshold level control on the rear of the unit. As the LED threshold is adjustable the green LEDs may either be used for simple level metering (perhaps set to +6dB) or they may be used to detect an active audio input when set to a lower threshold of around -20dB. The input channel LED will illuminate red to indicate that channel is peak distorting or clipping.
Matrix outputs are active and have an output impedance of 70 ohms. The level controls on the matrix outputs allow a gain range of off to +12dB.
An additional +12dB of gain is available using the multiturn preset controls marked +-. These preset controls have a gain range of off to +12dB and may be used to adjust gains so that the level controls conveniently sit in the 0 position making it easy to see if any levels have been adjusted. It would be expected these controls would be used when the unit used in fixed installations. As with the input LEDs, The output channel LEDs will illuminate green when the input level is over a preset threshold. This threshold may be adjusted for all output channels using the Output LED threshold level control on the rear of the unit. As the LED threshold is adjustable the green LEDs may either be used for simple level metering (perhaps set to +6dB) or they may be used to detect an active audio output when set to a lower threshold of around -20dB. The output channel LED will illuminate red to indicate that channel is peak distorting or clipping.