EnvelopeShaper processes the sounds by boosting or cutting the attack or decay. It does this by comparing the difference between two volume levels, one fast and one slow. You can use it to extend the sustain of a sound, or soften the attack, or do the opposite.

Attack sets the amount of gain for the attack phase of the sound. Positive values increase the gain of the attack producing more percussive sounds; negative values decrease the gain of the attack, creating a softer attack.

Decay sets the amount of the gain for the decay (i.e. non-attack) phase of the sound. Positive values increase the apparent sustain of the sound; negative values make the sound drier.

Atk Time determines how long it takes for the gain envelope to attack. In general, this doesn’t need much adjusting, but it’s available for fine tuning.

Lag: this control affects how long the attack phase stays on after an attack is detected. This will have a very noticeable effect on the sound, so experiment with different settings.

Hold: the attack phase is divided into two parts, hold and release. This setting determines how long the attack phase stays at its maximum value.

Curve sets the shape of the gain curve. Negative values are bottom-weighted, whereas positive values are top-weighted. 0% is linear.

Auto: this switch allows the volume of the output to change dependent on the settings of the Attack and Decay controls in order to prevent clipping.

In order for an attack to be detected, the volume differential has to exceed the Minimum plus the Range. The attack cannot retrigger until the volume differential goes below the minimum.

  • Min sets the threshold at which a sound is considered to be a release. Increasing this value will cause fewer attacks to be detected.
  • Rng controls how far about the Min level a sound has to be in order to be an attack.


Delay: sometimes you may find that the gain envelope is earlier or later than the incoming audio signal. If the gain envelope is out of sync with the input, use the delay control to compensate.

The Input, Output, and Gain switches in the lower right control the display of the various signals.