User manual

Amplitude and Brightness
CONTOUR (cont’d)
CONTOUR is a 4 Stage function generator that creates control voltages to drive the
DYNAMICS circuit, resulting in amplitude envelopes which greatly dene the sound of the
0-COAST. This approach takes inspiration from the original Loudness Contour circuit of the
MiniMoog, which is perhaps the most well-known and heavily-used example of East Coast
Synthesis.
ONSET sets the amount of time the circuit takes to travel to its maximum level, which is
where the sound will be loudest when CONTOUR is driving the DYNAMICS circuit. Setting
ONSET to Full Counter clockwise causes the sound to reach maximum level almost instantaneously, resulting in a very percussive,
impactful sound. As the ONSET Panel Control is set more clockwise, the circuit takes more time to travel to the maximum level:
the sound taking longer to fade into existence.
As soon as the CONTOUR circuit reaches the maximum level, it begins to DECAY to the SUSTAINing level where it remains for as
long as the Gate (e.g. from MIDI or Patched to CONTOUR Gate INput) is held HIGH or ON (Figure 50).
The SUSTAIN parameter determines this maximum
level, while DECAY sets the time it takes the circuit to
reach the SUSTAIN level. With SUSTAIN set to FULL
Counterclockwise, there is no SUSTAIN and the
CONTOUR immediately DECAYs to the minimum
level of 0V, or silence when driving the DYNAMICS
circuit, thus operating as a 2 Stage Function, similar
to the SLOPE circuit (Figure 51).
26
+8V
0V
Gate High
Gate Low
Figure 50: Typical Gate Signal
Figure 51: Contour Typical AD Function
+10V
0V
Attack Decay (AD): The Function is initiated once the Gate is received
at the MIDI INput Input,
at a Rate and Shape set by the ONSET and
VARI-RESPONSE Panel Controls and increases until it hits its maximum
value of 8V. Next, the SUSTAIN circuits alter the Function according to
the SUSTAIN Panel Control. Finally, the Function “Releases” back to 0V
at a Rate and Slope determined by the DECAY and Vari-Response Panel
Controls.
Note: Gate Length is ignored, as only the Rising Edge is “seen
by the input.
ATTACK DECAY
Time
Time
Figure 52:
Default Percussion Sound: [TAP] PGM_B to change rate.
(ONSET) (DECAY)