Vacuum has two modulation envelopes. By default, Env One modulates each filters’ cutoff frequency over time, and Env Two is used to do the same to the amplitude of Vacuum’s output. The envelopes can modulate other parameters, as well. See Vacuum Modulation Routing Controls. for more information.
Vacuum’s modulation envelopes have four main controls, A (Attack), D (Decay), S (Sustain) and R (Release).The amount of time it takes for the envelope’s modulation to reach its highest point when a MIDI note is received.The amount of time it takes for the envelope’s modulation to move from the top of the Attack phase to the level set by the Sustain control.The level at which the envelope stops while the current MIDI note is held. At zero, the envelope drops to zero by the end of the decay period, whether the note is held or not. At 100%, the envelope holds at its highest point until the note is released.The amount of time it takes for the envelope’s modulation to drop back to zero after a note is released. This control has no effect when sustain is at zero.Varies the effect that incoming MIDI note velocity has on the envelope's destination(s) (by default Filter Cutoff for Env One and overall volume for Env Two). All the way to the left, no change in modulation occurs.As the Vel control is moved to the right, more and more modulation occurs relative to incoming note velocity.