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EXi: AL-1 Analog Synthesizer
200
to these values may cause inconsistent behavior, or
may mean that the EG doesn’t reset at all. If this
happens, reduce the Threshold until the EG triggers
consistently.
7–1b: Envelope
EG
Envelopes create a modulation signal by moving from
one level to another over a specified time, and then
moving to another level over another period of time,
and so on.
The parameters below let you set five levels, the
amount of time it takes to go from each of the levels to
the next, and the shape (from linear to curved) of each
transition.
Level
Each of the five levels can be either positive or
negative.
Positive levels will make the cutoff frequency (or other
AMS destination) go up from its programmed value;
negative levels will make it go down.
Start [–99…+99]
This sets the initial EG level, at note-on.
Attack [–99…+99]
This sets the level at the end of the Attack time.
Break [–99…+99]
Break, short for Break Point, sets the level at the end of
the Decay time.
Sustain [–99…+99]
This sets the level at the end of the Slope time. Once it
reaches the Sustain level, the EG will stay there until
note-off, unless it is reset via AMS.
Release [–99…+99]
This sets the level at the end of the Release time.
Time
Higher values mean longer times, as shown below:
Attack [00…99]
This sets how long the EG takes to move from the Start
level to the Attack level.
The minimum attack time is 2/3 of a millisecond–as
fast as the most punchy of classic analog synths.
For the fastest possible attack time, you can set the
Start level to +99; in this case, the EG will start
instantaneously at its maximum value.
Decay [00…99]
This sets the time it takes to move from the Attack level
to the Break level.
Slope [00…99]
This sets how long the EG takes to move from the
Break level to the Sustain level. Once it reaches the
Sustain level, the EG will stay there until note-off
(unless it is reset via AMS).
Release [00…99]
This sets how long it takes the EG to move from the
Sustain level to the Release level.
Curve
For the sake of simplicity, most of the diagrams in this
manual show envelopes as being made out of straight
lines. In actuality, though, envelopes are more likely to
be made out of curves.
In other words, each segment’s level will change
quickly at first, and then slow down as it approaches
the next point. This tends to sound better than straight,
linear segments.
Classic analog synth envelopes made these curved
shapes naturally. The OASYS goes a step further than
vintage synths, however, and lets you control the
amount of curvature separately for each of the four
envelope segments.
When you change the curvature, the EG times remain
the same. However, greater curvature will tend to
sound faster, because the value changes more quickly at
the beginning.
Different curve settings for up and down
You may find that different amounts of curvature are
suitable for segments which go up and segments
which go down.
For instance, a curve of 3 is a good default setting for
upward segments, such as Attack. On the other hand, a
curve of 6 or more is good for downward segments,
such as Decay and Release.
EG Value Actual Time
00 0.667 ms
10 10 ms
20 44 ms
30 104 ms
40 224 ms
Note-on or reset
Note-off
Attack
Time
Start
Level
Decay
Time
Release
Time
Release
Level
Attack
Level
Change to
Parameter
Value
Sustain
Level
Time
Break
Level
Slope
Time
50 464 ms
60 944 ms
70 1.8 seconds
80 3.8 seconds
90 10.9 seconds
99 87.3 seconds
EG Value Actual Time