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HUSH
®
Function
The HUSH
®
function is accessible in all presets—regardless of the preset currently recalled.
HUSH is Rocktron's patented single-ended noise reduction system. The HUSH system contained in the Taboo Twin is a
fully digital implementation achieved through Digital Signal Processing (DSP).
The low level expander of the HUSH system operates like an electronic volume control. The analog version of the HUSH
utilizes a voltage-controlled amplifier (VCA) circuit which can control the gain between the input and the output from unity to
30, 40 or even 50dB of gain reduction. When the input signal is above the user preset threshold point, the VCA circuit remains
at unity gain. (This means that the amplitude of the output signal will be equal to that of the input signal.) As the input signal
level drops below the user preset threshold point, downward expansion begins. At this point the expander acts like an
electronic volume control and gradually begins to decrease the output signal level relative to the input signal level. As the
input signal drops further below the threshold point, downward expansion increases. A drop in the input level by 20dB would
cause the output level to drop approximately 40dB (i.e., 20dB of gain reduction). In the absence of any input signal, the
expander will reduce the gain so that the noise floor becomes inaudible.
The HUSH circuit is located after the A/D converter in the signal chain to reduce any noise generated from the guitar and
the A/D converter. This ensures a quiet input signal to the preamp section. Because the preamp section of the Taboo Twin is
digital, it is virtually noise-free (even in the high-gain mode). Therefore, a quiet input signal to the preamp will result in a quiet
output signal.
The P
ARAMETER
S
ELECT
control will allow you to access the following Hush
®
parameters:
Parameter
Description
HUSH I/O
The HUSH I/O parameter simply determines whether the HUSH® circuit is active for the current
preset.
HUSH
The HUSH THRESHOLD parameter determines the level at which downward expansion begins.
THRESH
For example, if the HUSH THRESHOLD was set at -20dB and the input signal dropped below
-20dB, downward expansion would begin.
