The FP-MX4 is a single-channel audio mixing module featuring four identical inputs. Each input accepts either a mic or line level source. The output section provides four mixing potentiometers corresponding to the four inputs. The output section provides both a balanced line (+4 dBu) and balanced microphone level (-45 dBu) output. Both outputs may be used at the same time. The four mixing potentiometers are intended to be set at installation or to be adjusted occasionally. Levels may be adjusted at the mixer using the RDL dual-LED VU meter which displays the mixer output level.