The Width slider determines the amplitude of the modulation sweep. This is displayed graphically in the modulation meter.
The Manual slider offsets the modulation sweep. This is displayed graphically in the modulation meter.
Click LFO or ENV to select the source for modulation. When the Source is set to LFO, modulation is controlled by the LFO. When it is set to Envelope (ENV), modulation is controlled by the Envelope Detector which listens to the audio signal. If the side-chain input in the Envelope section is activated, the side-chain audio is used instead of the current track.
Click Up or Down to change the direction of the modulation.