APPLIED ACOUSTICS SYSTEMS Strum Acoustic GS-1, Руководство пользователя

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54 Parameters
The phaser effects can be controlled with the three knobs appearing at the bottom of the module.
The Mix knob is used to adjust the ratio of “dry” and “wet” signal in the output signal of the module.
When the knob is adjusted in the left position, only the original or “dry” signal is sent to the output
while in the right position only the processed or “wet” signal is sent to the output. The
Depth knob
is used to control the amplitude of the effect while the Rate knob is used to fix the modulation
frequency of the effect when the Sync function is off .
6.4.6 Wah
The Multi-Effect module includes 2 different types of wah effects: wah wah, and auto wah. Both
of them are based on a specially designed bandpass filter with a 12 dB/oct slope. In the wah wah
effect, the center frequency of the bandpass filter varies at a certain rate. In the case of the auto-
wah, the variations of the center frequency is controlled by the amplitude envelope of the incoming
signal.
The Freq knob is used to control the central frequency of the filter. Turning this knob clockwise
increases the center frequency. In the case of the Wah Wah effect, the center frequency will oscillate
around the value fixed by the Freq knob while with the Auto Wah effect, the setting of the Freq will
fix the starting point of the value of the center frequency.
The Depth knob controls the excursion of the center frequency of the filter. In the case of
the Wah Wah effect, this excursion is applied around the value fixed by the Freq knob while in
Auto Wah effect the value of the center frequency increases from the value fixed by the Freq knob.
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. In the case of the Wah Wah effect, turning this knob clockwise increases the rate of the
modulation if the
Sync
function is
off
. In the case of the
Auto Wah
filter, this knob controls the time
constant of the envelope follower. Turning this knob clockwise decreases the time constant, or in
other words the reaction time, of the envelope follower.
6.4.7 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 outside of this band unchanged as
shown in Figure 24. As was the case for the
Wah Wah effect, the filter is based on a filter having a
12 dB/oct slope and can be modulated.
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 if
the
Sync function is off .