The ADSR Plot
ADSR is not unique to music synthesis, we have it in limiting and compression circuits, VOX (voice operated switching) and a multitude of electronic circuits where the human controller or sound engineer needs to modify or reshape original waveforms. The graph below shows the application control sequence.
In the plotting above one will note that the Attack control will take the volume or amplitude (it can be pitch as well), lift to a preset level and then allow a decay of the volume (or pitch) to a preset level which can be zero. Sustain holds the volume (or pitch) whilst release resets to a predetermined level.
Many older analogue synthesisers had an optional control, the “Hold” which allowed the holding of notes at sustain level before a decay, known as AHDSR. In most cases the “Hold” parameter was programmable but not the sustain. Design engineers don’t follow a rigid set of rules, whilst the individual control circuits may well have followed the same schematic it’s what happens in between that can make one machine more appealing than another -non conformity also makes one artist more unique than another.
The ADSR plot could be reversed as well, attacking from a high amplitude to a low. This is known as ADSR inversion.
This plotting of the ADSR is known as an “envelope shaper”whether it be amplitude, frequency or both.
AHDSFR: Attack, Hold, Decay, Sustain, Fade, Release
- Yusynth – modular designs
- Schmitzbits – some ADSR titbits
- Music from Outer Space – Analogue Synth – ADSR
The featured image is that of the Doepfer Dark Energy II – details found here.