Operation Manual

48 Parameters
4.3.9 Notch Filter
The Notch Filter does essentially the
opposite of a band-pass filter. It attenuates
the frequencies in a band located around
the center frequency and leaves those out-
side of this band unchanged as shown in Figure 28. As was the case for the Wah Wah effect, the
filter can be modulated.
Amplitude (dB)
Frequency (Hz)
0dB
−3dB
Center
Frequency
Band Width (Q=1)
Figure 28: Frequency response of a notch filter.
The Freq knobs is used to control the central frequency of the filter. Turning this knob clock-
wise increases the center frequency. The Depth knob controls the excursion of the center frequency
of the filter around its center frequency. Turning this knob clockwise increases the excursion of the
center frequency. Finally, the Rate knob controls the frequency or rate of the modulation of the
center frequency of the filter. Turning this knob clockwise increases the rate of the modulation.
Note that the Depth parameter is also adjustable from the Play view.
4.3.10 Reverb
The Reverb effect is used to recreate the effect of reflections of sound on the walls of a room or
hall. These reflections add space to the sound and make it warmer, deeper, as well as more realistic
since we always listen to instruments in a room and thus with a room effect.