Sequential Prophet VS - Page 128

128
CHIFF (#33)
This program demonstrates subtle use of noise in the mixer envelope,
producing a brief ute-like "chi" at the sound's beginning.
Keyboard Mode
The keyboard is in Single mode, but the programmed Split and Double
parameters can be activated by simply switching either keyboard mode switch
on.
When Double is switched on, program #36 (SLOWBELL) is activated, with a
3-cent detune and no delay between the two programs. Switching Split on
recongures the keyboard with program 36 playing to the left of the split point
(D#3), and the main program (CHIFF) to the right. In either Split or Double
mode, combining dierent programs with CHIFF is a simple matter of pressing
Link, then adjusting the underlined LINK PROGRAM value with the slider.
Oscillator Group
Stepping through the four oscillator settings with Oscillator Select, we nd that
--with the exception of oscillator A, which is set to white noise-- all oscillators
produce sine waves (wave #32) tuned to concert pitch (oscillator D), up one
octave (oscillator B), and up an octave and a fth (C). These pitches do not
battle for dominance in this program however, because they are controlled by
the mixer envelope.
Starting with essentially pure white noise at point 0, the mixer envelope quickly
moves to the opposite end of the A-C axis, producing the woodwind "chi"
eect for which the program is named. Such eects on analog synthesizers
are typically achieved by heavy ltering, which would also aect the tone of
the sustaining waveforms. The VS's dynamic mixing allows complex timbral
changes without modulating the lter at all.
Point 1 emphasizes the perfect fth produced by oscillator C, and is also the
only point at which oscillator B appears. Since rate 1 determines how fast
point 1 is reached, you can change the duration of the chi by simply adjusting
rate 1. Points 2 and 3 are essentially the same point. Once the mixer envelope
reaches point 2, the mix changes no further until the key is released. With
ALTERNATE RELEASE footswitch held, the fth becomes more apparent. (The
oscillator C component of point k is not heard when the amplier envelope
release rate is 0.)
Since oscillator C is tuned up a fth and an octave, the fth does does not
dominate the sound as it would were it an octave lower. Try it out —select
oscillator C and lower its coarse frequency to 7.
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