The Listen 4 by 4ms is a four-channel audio mixer that works perfectly as a backend mixer in a larger system. Inputs 1 and 2 are mono and have their own panorama controls, inputs 3 and 4 each have two sockets for true stereo. The only common inputs are the level control and the LED for monitoring the level of each channel.

The output level can be switched between modular and line level, additionally there is a separate volume control for the sum. Parallel to the master output there is a separately adjustable headphone output. At the back there are skirting boards for daisy chain operation, in order to be able to operate several Listen4 and/or Listen4 Quarters in a group.