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178 Chapter 14 The EVOC 20 PS
As you can see, there are some subtle differences between the two modes. We will look
at the common parameters first, and will then look at the mode-specific options.
Wave 1 Parameters
The footages below the Wave 1 label in both modes harks back to the days of pipe
organs. The longer the pipe, the deeper the tone. This also applies to Wave 1. Simply
click on the 16, 8 or 4 foot value to select the range in which Wave (oscillator) 1
functions. Your selection will be illuminated.
The numerical value beside the Wave 1 label (shown as 41 in the diagrams) indicates
the currently selected waveform type. The EVOC 20 PS features 50 waveforms with
different sonic characteristics. To switch between them, simply click-hold on the
numerical field and drag up or down. When the desired waveform number is visible,
release the mouse button.
Note: When in FM mode, the waveform of Wave 1 is a fixed sine wave. The waveform
parameter of Wave 1 does not have an effect in this mode.
Wave 2 Parameters
The numerical value beside the Wave 2 label (shown as 41 in the diagrams) indicates
the currently selected waveform type. The EVOC 20 PS features 50 single-cycle digital
waveforms with different sonic characteristics. To switch between them, simply click-
hold on the numerical field and drag your mouse up or down. When the desired
waveform number is visible, release the mouse button.
Noise Parameters
The Noise generator provides a further sound source which can be used in addition to
the two oscillators (Wave 1 and Wave 2).
The Level knob controls the amount of noise added to the signals of the two oscillators,
and the Color knob controls the timbre of the noise signal. When the Color knob is
turned fully-left, the Noise generator creates a pure white noise. When turned fully-right,
it generates blue noise (high-passed noise). White noise has always been used to create
wind and rain sound effects. It has the same energy in each frequency interval. Blue
noise sounds brighter, because its bass portion is suppressed by a high pass filter.
It is important to note that the Noise generator in the Oscillator section is independent
of the Noise generator in the U/V Detection section. For further information on voiced
and unvoiced signals, refer to “Analyzing Speech Signals”, from page 169 onwards.