The Classic ADSR envelope
The 'classic' envelope generator (EG) shape is often referred to as ADSR, referring to its four stages:
Attack, Decay, Sustain and Release.
The Attack setting of an envelope will determine how quickly it takes the Envelope to reach it's peak level. The smaller the value, the quicker the rise from zero to peak.
The next stage is the decay phase. The Decay setting controls the length of time it takes for the envelope to decrease in level from the peak to the level set by the Sustain control.
When the Envelope reaches the level set by the Sustain control, the envelope will remain at that level until a Gate Off signal triggers the entry of the last stage, the release stage. (See below for information about Gate signals).
The Release setting determines the speed at which the envelope will drop back to zero. Again, a small value will bring about a fast release time.
If a Gate Off message is received at any point before the Release phase is reached, the envelope will immediately enter the Release phase and the level will begin to drop.
Other types of Envelopes
Not all envelopes conform to the classic ADSR shape. Some do not have all of the stages mentioned above, whereas others offer the possibility of creating your own envelope shape with as many different stages as you wish.
AD envelopes These envelopes offer only two stages, Attack and Decay. The first setting determines how long it takes the envelope to reach its maximum value, the second how long it takes to return to minimum value once it has reached this peak.
AHD envelopes These envelopes offer Attack, Hold & Decay times. The settings determine how long it takes the envelope to reach its maximum level, how long it stays at that level, and how long it takes the envelope to return to zero.
MultiSegment envelopes These envelopes allow you to build your own envelope shapes using a graphical editor, with up to 99 separate points defined.
UniPolar vs. BiPolar
Envelopes which are to be used for controlling the volume of a signal are typically unipolar. This means that they only output positive values. BiPolar envelopes would be used for controlling aspects other than volume, which might be either positive or negative. With a BiPolar envelope there are two outputs, one 'positive' which outputs the envelope values as normal, the other negative which outputs an 'upside-down' version of the envelope values.
(It may be worth mentioning that in modular 1 the unipolar signal is actually a seperate datatype which has been dropped in modular II. With modular 1 envelopes you can't route unipolar signals through switches or mix them with other control signals. In modular 2 this works fine.)
Each EG has a Gate In connector which will typically be connected to the Gate Out of an MVC module, so that the Envelope is triggered by each note played on the keyboard will trigger the Envelope. It is possible to use other Gate Signal generating modules such as a Midi Clock Module to trigger the envelope automatically.
In order for the envelope to correctly function polyphonically, many envelopes also have an E-sync connection, which is used to ensure that, for example, the envelope triggered by note A isn't confused by a Gate Off message from Note B. If you are connecting an MVC to an EG and the Envelope you are using has an Esync Out (denoted by this symbol inVersion1 and this symbol in version 2 ) you should make sure that you connect the Gate Out from the MVC to the Gate In of the EG and the Esync Out of the EG to the Esync IN of the MVC.
|ADSR Simple Unipolar|
|Simple EG with input for modulation of envelope times according to velocity (Level Vel) or Keyboard position (TKF)|
|ADSR Simple Bipolar|
|As above, but with BiPolar output|
|As ADSR Simple UniPolar, but with inputs to modulate the ADSR values individually|
|As Simple ADSR Unipolar, but with controls to change the slopes of both Attack and Release curves between linear & exponential and with a separate AC output for control of pitch, filter frequency, etc|
|ADSR Vintage & Mod|
|As above, but with modulation inputs for all ADSR stages.|
|ADSR with Amp|
|ADSR EG with amplifier. Outputs both Audio signals as received at the Audio In as well as Envelope values via the AC or DC outputs.|
|ADSR with Stereo Amp|
|As above, but for stereo signals|
AD & AHD Envelopes
|Just attack and decay time can be set with this module|
|AD Vintage & Mod|
|Just attack & decay times again, but with the ability to modulate both these values|
|As above, but with a hold time, and modulation according to keyboard position|
|AHD Vintage & Mod|
|As above but with modulation inputs for Attack, Hold & Decay times|
|Multisegment Envelope Unipolar|
|These Multisegment envelopes allow you to define your own envelopes, with up to 99 seperate stages defined. You can also define a loop point between two stages, with a number of loops defined, so that the envelope cycles between these values until note off or until the number of loops has been reached.|
|Multisegment Envelope Bipolar|
|As above, but with the ability to output positive and negative values (according to whether the point is above or below the line.) No esync on this module as it's intended for control values, not Amp control.|
Here are a couple of files showing what you can do with an envelope modulating a filter (as opposed to the amplitude of a patch.)
These examples were done with the Solaris patch from the Mystic Journey patch.
Firstly, here's the Solaris patch with the envelope which modulates the filter set to a quick attack and quick release like this:
Solaris Quick (90kb)
Now listen to exactly the same note played with the following envelope settings:
Solaris Slow (90kb)
Nothing else about the patch has changed in any way, but notice how much more dynamic the patch becomes when the filter is opened slowly in this way.