Arturia KeyStep Pro Keyboard with Advanced Sequencer and Arpeggiator - Manual (Page 100)

5.4.2. Gates and Triggers
The keyboard, the sequencers (including the Drum sequencer) and the arpeggiators create
gates and triggers. Gates and triggers are needed to start envelope generators (EGs) in
external synths or Eurorack modules. By itself, an envelope generator does nothing; it needs
a gate or trigger to start.
It is essential to understand that gates and triggers are two different things. A trigger is a
very short pulse that can be used to synchronize (sync) modules with each other or, as in the
KeyStep Pro, to start envelopes. A gate is usually longer: anywhere from a few milliseconds
to several seconds.
The KeyStep Pro keyboard is the primary source of gates. When your finger touches a key
on the keyboard and holds it down for a moment, you generate a gate. The gate goes into
the ON state when you press the key down; it goes into the OFF state when you release the
key by lifting your finger off it. When transmitted via MIDI (Out 1, Out 2 and USB) or via one
of the four Voice Gate outputs, this gate signal starts an envelope cycle and the first stage of
the envelope, the attack, begins. The duration of this increase in level depends on the attack
setting (A) of the envelope generator. The envelope then continues through the decay stage,
the duration of which depends on the decay setting (D), to the sustain stage, which has a
constant level (S). It remains in the sustain stage until you lift your finger off the key. Then
the final stage of the envelope begins: the release, during which the level decreases to zero.
The duration of this decrease depends on the release setting (R) of the envelope generator.
It is important to realise that the KeyStep Pro does not generate ADSR envelopes, nor can it
control their parameters (A, D, S and R). The KeyStep Pro only generates gates and triggers.
94 Arturia - User Manual Keystep Pro - Making Tracks