Envelope generator

The envelope generator (EG) generates a traditional ADSR envelope. The envelope defines how the level changes with time and is controlled by the Attack, Decay, Sustain and Release parameters. Its function is to modulate a parameter over time, based on MIDI input or the amplitude of an audio signal that triggers it.

To add an envelope generator as a modulation source, click the + button in the modulation section and click New Envelope Generator.

Initially the EG is shown as a source component button in the interface, showing a graphical representation of the current settings. For more information on working with source component buttons, see Modulation.

Click the source component button once to expand the full EG interface:

The expanded interface contains a large graphical envelope controller with triggering controls on the left.

• The trigger input button opens a menu to select which signal is used for triggering the EG: the main input signal, the signal from the external side-chain input, or MIDI note on events. See also External side chaining.

• An audition button becomes visible when triggering on the external side-chain. Click and hold it to temporarily listen to the signal this EG is triggering on.

• The threshold knob sets the level of the incoming signal that the EG will trigger on. You should adjust the threshold depending on the type and amplitude of the incoming signal. The circular level meter around the threshold knob gives a good indication of what threshold level to use. Note: the threshold knob is hidden when MIDI input triggering is used.

• The range button selects whether the EG produces a signal in the default range between 0 and 1, or with a range such that the EG outputs 0 while in its sustain phase. In the latter case, the EG will attack from a negative value to a positive value, and finally release to a negative value. This "centers" the output value around 0, which can be useful for modulation.

In the envelope controller you can click and drag the dots to customize the envelope shape. The following parameters are available:

• Delay
  The time it takes for the attack to start after the key is pressed (or triggered when the input signal exceeds the threshold).

• Attack
  The Attack portion of the envelope is the time taken for the amplitude to reach maximum value. Slow attack is commonly part of sounds called pads. But for percussive sounds the attack time should be as short as possible.

• Decay
  After the sound has reached its maximum level, it starts to decay until it reaches a level known as the Sustain level at a rate set by the Decay time setting.

• Sustain
  This is the level reached after the decay time. The EG will hold this level as long as a key is pressed (or as long as the trigger input level is above the threshold). Note that this parameter specifies a volume level rather than a time period.

• Hold
  Once the key is released (or the input level drops below the threshold), the value will remain at the sustain level for a time set by the hold parameter.

• Release
  After the hold time the sound resumes its decay, this time at a new rate determined by the Release setting.

• Attack, Decay and Release Slope
  The attack, decay, and release curves each have a slope dot in the middle that you can drag up and down to vary the curve shape between linear, logarithmic and exponential behavior. This lets you customize each of these curves to change its feel and snappiness and makes the EG much more versatile.

Tips

• When adjusting the EG control points, you can hold down the Shift key to fine-tune a setting, just like with regular knobs.
• To let a sustain pedal control the EG, you can hook it up to the Hold setting. The recommended way to do this is via a MIDI source.

Next: Envelope follower

See Also
Modulation
Drag-and-drop modulation slots