FM synthesis is, at its core, caused by the intensity and type of modulations that take place in the signal path. The modulators outlined in this section have a different impact and role to play than equivalent envelopes and LFOs found in analog synthesizer designs.
Modulation Envelope sliders: Control both the FM (Intensity) and Modulator pitch parameters over time. The envelope is triggered every time a MIDI note is received.
Attack slider: Set the time it takes to reach the maximum envelope level.
Decay slider: Set the time it takes to reach the sustain level.
Sustain slider: Set a level that is held until the MIDI note is released.
Release slider: Set the time it takes to reach a level of 0, after the MIDI note has been released.
Modulator Pitch knob: Determine the impact of the modulation envelope on the pitch of the modulator oscillator.
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 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.