ENSONIQ ESQ-M, Musician'S Manual

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Understanding the Envelopes
ESQ-M – Musician's Manual
UNDERSTANDING THE ENVELOPES
An Envelope is a shape, or "contour" that we apply to some signal source to make it change through time. Naturally
occurring sounds have their own Envelopes. They don't just start and stop — they might start loud and fade to
silence, or slowly swell from silence to a huge crescendo; they might start out very bright and grow duller; they might
have subtle variations in pitch, and so on.
In a synthesizer we imitate these effects, and create wholly new ones, by generating Envelopes and then using
them to modulate pitch, volume, brightness, etc. The ESQ-M has four Envelopes which can be independently
assigned as modulation sources to the various OSC's, DCA's, LFO's, PAN and the FILTER.
The ADSR Connection -
Let's start by taking a look at the commonly used ADSR (Attack, Decay, Sustain, Release) type Envelopes
found on many synthesizers. With the ADSR Envelope, the name says it all. You have four parameters to
control:
Attack — The Time it takes to go from zero, when a key is struck, to peak level Decay — The
Time it takes to go from the peak level to the Sustain Level Sustain — The Level at
which the signal remains as long as the key is held down
Release —
The Time it takes to return
to zero after the key is released
ADSR Env elop e
Notice that an Envelope is really just
a series of Levels that change through
Time. With the four
parameters of the ADSR Envelope, we can control three Times (Attack, Decay and Release) and one Level
(Sustain). This is fine for many basic volume and brightness Envelopes, but for more complex sounds — for
subtle pitch Envelopes and other cool effects — it becomes necessary to have more specific control over more
Times and
Levels.
Which brings us back to the ESQ-M.
Times and Levels
The four Envelopes on the ESQ-M are defined in terms of Time and Level. For each Envelope, you have
control over four Time segments (TIME 1, TIME 2, TIME 3, and TIME 4) and three Levels (LEVEL 1,
LEVEL 2 and LEVEL 3).
When a key is struck, the Envelope level, starting at Zero, takes a fixed amount of time, defined by TIME 1, to
reach LEVEL 1. It then takes TIME 2 to reach LEVEL 2. Next, at the end of TIME 3 it reaches LEVEL 3,
where it will remain as long as the key is held down. After the key is released the signal takes TIME 4 to
return to Zero.
The three Level parameters appear on each Envelope Page as [LEVEL 1], [LEVEL 2] and [LEVEL
3]; the four TIME parameters as [TIME 1], [TIME 2], [TIME 3] and [TIME 4]. The figure on the next
page shows a typical Envelope as defined by the ESQ-M Envelope parameters: