The signal processor shall be mounted in a steel chassis six inches deep and one rack unit high. The unit shall be a Zoner/Mixer, i.e, it shall accept inputs from four separate stereo sources and composite video sources as well as a microphone, and send them to two separate zones.  A switch on the rear panel shall switch the output of the two zones to either stereo (Left and Right), or Mono.
 
The microphone input shall have a level control and two way Equalisation controls. The microphone connector shall be a balanced XLR input with an Input impedance of 4 K Ohms. There shall also be  an input for a ducker control to attenuate line inputs by 20 dB, and LEDs to indicate microphone status. The microphone shall be able to be routed to either or both output zones.

Each Line source shall have High Z Left and Right phono (RCA type) connectors, with associated Gain trim controls –10dB to +10 dB on the rear panel, and an overall line level control on the front panel. A switch and status LED on the front panel shall indicate which source is active in each zone. These switches shall be interlocking so that only one of the four input sources per zone can be selected at one time.
Each Zone shall have an Equalisation control and the option of Local or Remote Master output level control. Each Master output shall have a dedicated 5 LED metering display
Input source impedance shall be 100K Ohms, and the input headroom shall be +21dB. 

The frequency response (all channels and masters) shall be 20 Hz to 20 KHz, ±1dB. The Output impedance shall be 300 ohms balanced, and the maximum Output level shall be +21dB, with a Signal to Noise ratio at unity of -90 dB ‘A’ weighted. Audio Output connectors shall be Balanced XLR type; Video Output connectors shall be RCA type. THD shall be below .005%, 100Hz to 10 KHZ, and the unit shall have a dynamic range of 111dB.

Power shall be supplied via a removable mains cable, connecting to an IEC connector with an integral fuse and voltage change switch on the unit’s rear panel.
The Zoner/Mixer shall be the ARX AV Stream.