Operation Manual

32 Parameters
The Drive control is a gain knob acting on the input signal. This parameter allows one to adjust
the amount of distortion introduced in the signal by controlling how rapidly the signal reaches
the non-linear portion of the distortion curve applied on the signal. In its leftmost position, the
amplitude of the input signal is reduced by -6 dB; turning this knob clockwise allows one to increase
its amplitude. Note that the Drive parameter is also adjustable from the Play view.
The Tone knob is used to adjust the color of the signal after the distortion algorithm has been
applied. In its leftmost position, high frequencies will be attenuated in the signal while in its
rightmost position low frequencies will be filtered out from the signal. In its center position, the
signal will be left unchanged.
The Volume knob is a gain knob acting on the amplitude of the distorted signal. Finally, the Mix
knob allows one to control the amount of dry and wet (distorted) signal in the final output signal
from the Distortion module. In its leftmost position, there is only dry signal in the output while
in its rightmost position one only hears the distorted signal. In its center position, there is an equal
amount of dry and wet signal in the output.
5.3.5 Chorus
The chorus effect is used to make a source sound like many similar sources played in unison. It
simulates the slight variations in timing and pitch of different performers executing the same part.
The effect is obtained by mixing the original signal with delayed version obtained from the output
of delay lines as shown in Figure 13. In the case of a chorus effect, the length of the delay lines must
be short in order for the delayed signals to blend with the original signal rather than be perceived as
a distinct echo. The length of the delay line can be modulated introducing a slight perceived pitch
shift between the voices.
Tuning
The amount of modulation of the length of the delay lines is adjusted using the Depth knob. In the
left position, there is no modulation and the length of the delay lines remains constant. As the knob
is turned to the right, the length of the delay line starts to oscillate by an amount which increases
as the knob is turned clockwise thereby increasing the amount by which the different voices are
detuned. The frequency of the modulation is fixed with the Rate knob.