If you click the “0” to center the Modulator Pitch knob, the envelope has no effect on the pitch of the modulator oscillator.
FM Depth knob: Determine the impact of the modulation envelope on FM intensity.
If you turn the knob clockwise, you increase the effect of the modulation envelope. If you turn the knob counterclockwise, you invert the effect of the modulation envelope, as follows: the envelope slopes down during the attack phase and slopes up during the decay and release time phases.
If you click the “0” to center the FM Depth knob, the envelope has no effect on FM intensity.
LFO knob: Set the amount of modulation applied to FM intensity or pitch.
If you turn the LFO knob clockwise, you increase the effect of the LFO on FM Intensity. If you turn the knob counterclockwise, you introduce a vibrato.
If you click the “0” to center the LFO knob, the LFO has no effect.
Rate knob: Set the speed of the LFO.
Download the guides:
Logic Pro User Guide: PDF
Logic Pro Effects: PDF