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17
Oscillators
ning of the sound and rest at a final pitch. Finally turn the OSC
1-2 sync on by sliding the switch to the ON position.
Experiment with the sound by raising the semitone pitch of
OSC 2 and by adjusting the MOD ENV ATTACK and DECAY
knobs in the Envelopes section.
PWM (Pulse Width Modulation) Source switch
and
Pulse
Width knob
The function of the PULSE WIDTH knob is dependent on the
PWM SOURCE switch.
With the switch in the MANUAL position, the PULSE WIDTH
knob will manually control the pulse width of a square wave-
form (The selected waveform for the Oscillator must be Square
for this to happen). In order to understand how the Pulse Width
knob affects other waveforms see the paragraph following titled:
Width control of other Waveforms.
With the PULSE WIDTH knob in the central position, the Pulse
Width wave becomes a square wave. As the knob is adjusted
clockwise, or anticlockwise, the Pulse Width becomes narrower,
producing thinner more nasal sounds.
With the PWM SOURCE switch in the LFO 2 position, the width
of the Pulse Wave may be modulated by either LFO 2, or, when
the FUNCTION switch is set to SHIFT, the MOD ENV. The
intensity of this modulation is determined by the PULSE WIDTH
knob. With the Pulse Width knob at central position there is no
effect. Turning clockwise or anticlockwise introduces the effect.
Continuous variation in the width of a pulse waveform (which is
what is happening when LFO 2 is modulating it) changes the
harmonic content. This is pleasing to the ear, especially at
lower pitches where all the associated harmonics fall within the
audio range.
When modulated by the MODE ENV, the effect is most appar-
ent when using fairly long Mod Env Attack and Decay times.
Width control of other waveforms
If the square wave is not selected for the Oscillator being
adjusted by the pulse width control, its waveform will gradually
change to a double waveform of the same type as the pulse
width control is moved away from its central position.
Very thick sound textures may be created by using LFO2 to
modulate this doubling effect. To hear the effect, select a saw-
tooth waveform for one of the Oscillators. Set the PWM
SOURCE switch to the LFO2 position. Set LFO2’s waveform to
triangle. Introduce an amount of modulation from LFO2 by
moving the PULSE WIDTH knob from its central position.
Adjust the speed of LFO2 and notice how the speed affects the
apparent detuning ‘thickening’ of the sound.
Main features and operation