Operation Manual

4.3 The FX View 45
0 dB
Amp
Frequencyf0
2xf0 3xf0 4xf0 5xf0 6xf0
Feedback = 0.9
No Feedback
Feedback = 0.5
Figure 25: Effect of the amount of feedback on the frequency response of a Flanger module.
turned clockwise and at a frequency fixed with the Rate knob. The Feedback knob is a gain knob
used to fix the ratio of wet signal re-injected into the delay. Finally, the Mix knob determines the
amount of dry and wet signal in the output signal from the module. When this knob is adjusted in
its leftmost position, only dry signal is sent to the output, in its center position, there is an equal
amount of dry and wet signal in the output signal while in its rightmost position, only wet signal is
sent to the output. Note that the Depth parameter is also adjustable from the Play view.
4.3.7 Phaser
The Phaser module implements the effect known as phasing which colors a signal by removing
frequency bands from its spectrum. The effect is obtained by changing the phase of the frequency
components of a signal using an all-pass filter and adding this new signal to the original one.
The algorithm implemented in this module is shown in Figure 26. The input signal is sent into a
variable all-pass filter. This wet signal is then mixed down with the original dry signal. A feedback
line allows the resulting signal to be re-injected into the filter. The effect of the Phaser module is
to introduce rejection in the spectrum of the input signal depending on the tuning of the filter.
The all-pass filter modifies a signal by delaying its frequency components with a delay which
increases with the frequency. This phase variations introduce a certain amount of cancellation when
this wet signal is mixed down with the original dry signal as shown in Figure 27. The rejection is
maximum when the phase delay is equal to 180 degrees and a given component is out of phase with
that of the original signal. The amount of effect is determined by the ratio of wet and dry signal
mixed together as shown in Figure 27. As the amount of wet signal sent to the output is reduced, the