ES1 offers a number of simple yet flexible modulation routing options. You use modulation to add animation to your sound over time, making it more interesting, lively, or realistic. A good example of this type of sonic animation is the vibrato used by orchestral string players.
LFO parameters: Used to modulate other ES1 parameters. See Use the ES1 LFO.
Router: Enables you to choose the ES1 parameters that are modulated. See Use the ES1 router.
Modulation Envelope: A dedicated modulation control source that can be used to control various ES1 parameters, or it can be used to control the LFO level. See Use the ES1 modulation envelope.