[Nitrox 1.11]

As the insiders know, ADSR stands for Attack, Decay, Sustain and Release, the four characteristical phases of the amplitude development of a sound. Attack is the first very characteristic phase where the amplitude rises to the maximum level. In the Decay phase the amplitude decays to the so-called sustain level. Usually the amplitude stays there until the keyboard is released (MIDI note off). This is the beginning of the release phase where the amplitude drops to zero in a certain amount of time. In naturally sounding amplitude courses the change during attack, decay and release follows an exponential function with negative exponent. The higher the nominal value of the exponent the more quickly the next level is reached.

Besides amplitude, other characteristics of a sound like spectrum are also often controlled by an ADSR. In this case the ADSR serves as a modulation input e.g. for the filter cutoff frequency.

Nitrox comprises five independent ADSR units which are a little bit more sophisticated than the classical ones described above. See the parameter section below for additional features.

The ADSR amplitude development is also called envelope. Note, that Nitrox additionally provides completely customizable envelope generators.


  1. Trigger
  2. Type
  3. Sense
  4. Delay
  5. Attack
  6. Decay
  7. Sustain
  8. Fade
  9. Release


An ADSR is triggered by note on (attack) and note off (release) events. Trigger lets you configure where these events originate from. This can be either directly from the MIDI input or from one of the five mini sequencers allowing complex one-shot or repeating patterns. A trance gate can be realized very quickly with this feature.



Type sets the function type used during the amplidude development. It can be either linear or one of several differently steep exponential functions.



Sense determines how much the velocity of the note on event is taken into account, in order to make the envelope's maximum level dependent on the intensity of the keyboard stroke. A value 0% means no dependency but maximum envelope level, a value of 100% means the evelope level follows completely the note velocity.



Delay is given in milliseconds and determines the time between note on and the start of the attack phase.



Attack is the time in milliseconds for the rise of the amplitude to the maximum level.



Decay is the time in milliseconds for the decay of the amplitude from the maximum level to the sustain level.



Sustain is level to be reached after the decay phase measured in percent of the maximum value.



Fade is an enhancement of the classical ADSR. It is the time in seconds within which the sustain level decays to zero, usually very slowly.



Release is the time in milliseconds for the amplitude to decay to zero after the note off event has occured, i.e. the keyboard was released.



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