Rocktron Reaction HUSH - Manual (Page 10)

HUSH Information
In most applications, the signal from an instrument
being played is much louder than the noise
level. Therefore, much of the noise is not heard
when an instrument is being played. However,
when you stop playing or let a note decay, the
instrument level drops below the noise level and
the noise becomes much more audible. Setting the
THRESHOLD controls just above the level of the
noise causes The Pedal to begin to decrease the
output level so that the noise is never heard.
The Pedal incorporates the latest advancements in
HUSH noise reduction technology. HUSH The
Pedal’s discrete threshold control circuit utilizes a
voltage-controlled amplifier (VCA) as a downward
expander which can control the gain between the
input and output of The Pedal from unity to over
60dB of gain reduction. When the input signal is
above the threshold level set by the THRESHOLD
control, the VCA will remain at unity gain (i.e. the
output level will remain equal to the input level).
As the amplitude drops below the threshold point,
downward expansion will begin.