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240 Chapter 22 ES2
White and Colored Noise (Oscillator 3 only)
Unlike Oscillator 2, Oscillator 3 is not capable of producing ring modulated signals nor
sine waves. Its sonic palette however, is bolstered by the inclusion of a noise generator.
By default, Oscillator 3’s noise generator generates white noise. White noise is defined as
a signal that consists of all frequencies (an infinite number) sounding simultaneously, at
the same intensity, in a given frequency band. The width of the frequency band is
measured in Hertz. Its name is analogous to white light, which consists of a mixture of
all optical wavelengths (all rainbow colors). Sonically, white noise falls between the
sound of the consonant F and breaking waves (surf). Synthesis of wind and seashore
noises, or electronic snare drum sounds, requires the use of white noise.
Screenshot of a white noise sample, showing the output signal of Oscillator 3.
Oscillator 3 has more up its sleeve than the output of neutral sounding white noise—
you also can make it hiss or rumble. Even better, you can modulate this sound color in
real-time without using the main filters of the ES2.
If the waveform of Oscillator 3 is modulated, (Osc3Wave) the color of the noise will
change. It can be filtered by a dedicated highpass or lowpass filter with a descending
slope of 6 dB/octave. At negative values, the sound becomes darker (red); The lowpass
filter can be tuned down to 18 Hz with a setting of −1. When Osc3Wave is modulated
positively, the noise becomes brighter (blue): At a value of +1 for Osc3Wave, the
highpass filter’s cutoff frequency is set to 18 kHz. This filtering of the noise signal is
independent of the main filters of the ES2, and can be automatically changed in real-
time.
Oscillator Mix Field—the Triangle
By grabbing, and moving the cursor in the Triangle, you can crossfade between the
three oscillators. This is pretty self-explanatory. Moving the cursor along one of the
Triangle’s sides will crossfade between two oscillators, with the third oscillator being
muted.