The Mutronics Mutator from Softube is an analog voltage controlled filter software plug-in based on analog synthesis technology from the '60s and modeled after the early '90s hardware unit. The Mutator features two channels, each with an envelope follower, LFO, voltage controlled amplifier, and side-chain input. Additionally, the unit offers a stereo width control, dry/wet mix control, and a volume control. The plug-in is well suited for any audio source and creates mind-boggling filter effects.
The Env Follower section tracks incoming audio and sends a signal to the filter. An Int/Ext switch provides signal routing with the Int or internal setting following the input source, while the Ext or external setting takes a feed from the side-chain input and allows for a secondary source to control the envelope. Additionally, the envelope follower can be triggered by a gate and forces the circuit to behave in a full on or off mode. There are sensitivity, attack and release controls for further shaping the signal which are passed to the filter's Env Sweep control.
The LFO section offers triangle, square, ramp up, and ramp down waveforms, as well as rate and depth controls. A switch selects whether the LFO controls the filter, amplifier, or both. The Link In/Out switch locks the LFO settings for both channels, while the invert switch causes the right channel to be 180° out of phase with the left; creating some interesting stereo effects. Additionally, there is a tempo lock, which allows the LFO to follow the DAW's host tempo and deactivates the rate knobs.
The Filter Section offers controls for cutoff, resonance, and envelope sweep, which determines how the envelope follower sweeps the filter up or down. A VCA switch routes the signal through the voltage controlled amplifier or takes the signal direct from the filter output.
The Output section offers a dedicated volume knob to control the plug-in's overall output, while the mix knob controls a blend of the original or processed signal. The width knob acts as a Mid/Side matrix with the narrowing of the stereo field when turned counter-clockwise and the widening when turned clockwise.