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Table Of Contents
206 Chapter 20 ES2
The Waveforms of Oscillators 2 and 3
Basically, Oscillators 2 and 3 supply the same selection of analog waveforms as
Oscillator 1: sine, triangular, sawtooth, and rectangular waves. The pulse width can be
scaled steplessly between 50% and the thinnest of pulses, and can be modulated in a
number of ways (see the “Pulse Width Modulation” section, on page 206).
Oscillators 2 and 3 also offer the selection of:
 A rectangular wave, synchronized to Oscillator 1
 A sawtooth wave, synchronized to Oscillator 1
 A ring modulator, which is fed by the output of Oscillator 1 and a square wave from
Oscillator 2.
 Colored noise for Oscillator 3
Synchronization and ring modulation facilitate the creation of very complex and
flexible harmonic spectra. The principle of Oscillator synchronization is described on
page 207, and ring modulation on page 207.
Pulse Width Modulation
Oscillators 2 and 3 allow you to scale the width of the pulses to any value. The
spectrum and tone color generated by these oscillators depends on the pulse width.
The pulse width can be modulated. You can even modulate the pulse width of the
square and pulse wave of Oscillator 1, the pulse width of the synchronized pulse waves
of Oscillator 2 and 3, and the square wave of Oscillator 2’s ring modulator.
This width modulation is controlled in the Router (the Modulation Matrix). The pulse
width is defined by the waveform rotary control. The graphic below shows a pulse
wave, with the pulse width modulated by an LFO. You can clearly see how the width of
the pulses change over time.
Note: A pulse wave (with its width modulation controlled by an LFO set to a sine wave)
makes a single oscillator sound vivid, undulating, and rich with overtones. Sonically,
this is somewhat like the sound of two slightly detuned, phasing oscillators. The effect
sounds great with sustained bass and pad sounds. Select the intensity and speed of the
modulation with care, as the overall volume (and level of the first partial) decreases,
and slight detuning occurs, when the pulses become very thin (below 10%). Pulse
width modulations via velocity sensitive envelope generators sound very dynamic—a
great effect that is especially suitable for percussive bass sounds.