Operation Manual

4.2 The Edit View 35

The envelope modules generate a four segment envelope:

attack, decay, sustain, release. The attack time is adjusted us-

ing the Attack knob. The attack time can also be modulated

with the velocity signal received from the MIDI keyboard to

make the attack time shorter as the velocity increases, the in-

tensity of this effect being controlled using the Vel knob on the

left of the Attack knob. When this knob is in its leftmost po-

sition, the attack is only determined by the value of the Attack

knob, turning the knob clockwise increases the inﬂuence of

the velocity signal until the attack time is strictly determined

by the inverse of the velocity signal when the Vel knob is fully

turned to the right. The decay time is set with the Decay knob.

The sustain phase of the envelope generator lasts from the end

of the decay phase until the key is released. When the Sustain

knob is fully turned to the left, the sustain level is zero and

there is no sustain phase while fully turned to the right, the

sustain level is at maximum and there is no decay phase. When the key is released, the envelope

generator toggles to the release phase and the envelope signal decreases from the value at the end

of the sustain phase to zero in a time set by the Release knob.

Note that during the sustain phase, the envelope signal can be made to decrease even if a key

is still depressed. The time taken to go from the level set by the Sustain knob to a value of zero

is then determined by the value of the Time knob located below the Sustain knob. When the Time

knob is fully turned to the left, the envelope signal falls to zero right after the end of the decay

phase; when the knob is in it rightmost position, the sustain level is held as long as the key is

depressed. Finally, the overall level of the envelope can be controlled with the velocity signal from

the keyboard through the Vel slider located to the left of the Sustain knob and behaves in exactly

the same way as the Vel parameter associated with the Attack knob.

Shape of the Envelope Segments

We have so far determined the shape of the envelope by adjusting the duration of the different

phases as well as their level. The envelope signal can further be modiﬁed by adjusting the shape

of the envelope segments. These are linear when the Exp button is in its off position and become

exponential when it is switched on as shown in Figure 17.

Free Run Mode

The Free button sets the envelope into free-run mode. This allows one to bypass the sustain phase

of the envelope or in other words, to go directly from the decay phase to the release phase regardless

of the amount of time a key is depressed.