The MX40 is a four-channel noise gate with a tunable or frequency conscious input controls. Pairs of channels may be linked for stereo and the whole unit takes up just one rack space. A broad band expander called Peak Punch is used for a maximum of 8dB of transient expansion to gated signals and nearly zero attack time following gate opening. Gated signals are said to "punch" through the mix without adding significant average level.

Each gate section has controls for threshold, release time and trigger frequency selection. There are push button switches for gate opening dynamics and a gating range of 20dB or 90dB attenuation. There are also external key inputs for gating control from another source and a trigger filter in/out switch. A key listen feature let you monitor the sound of the triggering signal. Input and output connections are balanced XLRs while the key inputs are 1/4 inch. Finally, an LED "traffic" light indicates gate status.