Sequential Prophet Rev 2 - Oscillators; Oscillator Parameters and Features

26
27Filter Envelope
Sequential Prophet Rev2 User’s Guide
Amplier Envelope
Delay: 0...127—Sets a delay between the time the envelope is triggered
(note on) and when the attack portion actually begins.
Attack: 0...127—Sets the attack time of the envelope. The higher the
setting, the slower the attack time and the longer it takes for the lter to
open from the level set with the lter cutoff knob to the level set by the
lter envelope amount. Percussive sounds typically have sharp (short)
attacks.
Decay: 0...127—Sets the decay time of the envelope. After a sound
reaches the lter frequency set at its attack stage, decay controls how
quickly the lter then transitions to the cutoff frequency set with the
sustain knob. The higher the setting, the longer the decay. Percussive
sounds, such as synth bass, typically have shorter decays (and a generous
amount of low-pass lter resonance).
Sustain: 0...127—Sets the lter cutoff frequency for the sustained
portion of the sound. The sound will stay at this lter frequency for as
long as a note is held on the keyboard.
Release: 0...127—Sets the release time of the envelope. This controls
how quickly the lter closes after a note is released.
Amplier Envelope
After passing through the lters, a synthesized sound goes into an analog
voltage controlled amplier or VCA, which controls its overall volume.
The VCA has a dedicated, ve-stage envelope generator (DADSR).
The Amplier Envelope is used to shape the volume characteristics of a
sound over time by giving you control over its attack, decay, sustain, and
release stages (plus a delay parameter to delay the onset of the envelope).
Along with the lter envelope, this is one of the most important factors in
designing a sound.
Without a volume envelope, the volume of a sound wouldn’t change
over the duration of a note. It would begin immediately, remain at its full
volume for the duration of the note, then end immediately when the note
was released. Again, that’s not very interesting sonically and it’s not typi-
cally how instruments behave in the real world.
To give you a real-world example, the main difference between the sound
of the wind and the sound of a snare drum is that they have very different
volume envelopes. Otherwise, they are essentially both white noise.
Wind has a relatively slow attack, a long sustain, and a long decay and
release. A snare drum has a sharp attack, no sustain, and very little decay
or release. But again, they are both fundamentally white noise.
AMPLIFIER
PAN SPREAD
ATTACK
ENV AMOUNT
DECAY
VELOCITY
SUSTAIN
DELAY
RELEASE
Amplier Envelope