Dave Smith Instruments PROPHET 12 KEYBOARD - Manual (Page 32)

22 Voltage Controlled Amplifier Dave Smith Instruments
Voltage Controlled Amplifier
After passing through the filter stages, the signal goes into an analog
voltage controlled amplifier or VCA. The VCA has a dedicated, five-
stage envelope generator. (See Low-Pass Filter on page 18 for an
illustrated example of an envelope generator.) There is a control for
modulating the envelope amount using keyboard velocity, as well as a
control for left/right spread of the voices in the stereo field.
Envelope Amount: 0...127 —Sets the amount of modulation
from the amplifier envelope to the VCA. See the following item,
Velocity
’
Envelope Amount, for information about setting a program’s
velocity sensitivity.
Velocity’Envelope Amount: 0...127 —It’s very easy to misunderstand
what this control does. It enables keyboard velocity to modulate the
VCA Envelope Amount. What it does not do is use keyboard velocity to
directly control the VCA.
To create a program in which velocity controls the VCA, turn VCA
Envelope Amount down and turn Velocity
’
Envelope Amount up.
To achieve the best results, it may be necessary to set an initial level
using Envelope Amount. Just remember that once Envelope Amount
is set to the maximum, no modulation from velocity—or any other
source—will cause it to go higher than that.
Program Volume: 0...127 — Sets the volume of the current program to
match volumes between programs.
Note: There is enough gain in the synth voice that, with some
settings, some mild clipping distortion may be heard. If this happens,
try lowering the P
rogram
V
olume
, and/or the VCa e
nVeloPe
a
mount
(or VCa V
eloCity
e
nV
a
mount
).
Pan Spread: 0...127 —Pans the audio in the stereo field individually
per voice. Set to 0, all voices are panned to the center. As Pan Spread
is turned up, the audio in each voice is gradually moved away from the
center by different amounts. Every other voice goes in a different direc-
tion, left or right. This creates a broader stereo field while playing. Any
modulation to Pan will individually move each voice from its position as
set by Pan Spread.