5.4
The Effects View
57
5.4.5
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 33. 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.
Figure 33:
Chorus
module.
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.
The
Fat
button is used to control the number of voices in the chorus effect. Switching this button
on
increases the number of voices. The
Spread
knob is used to adjust the amount of dispersion of
