User`s manual

AEQ FORUM - DIGITAL AUDIO MIXER FOR BROADCAST APPLICATIONS
83
When establishing the settings, the threshold for the noise gate will be much lower than in the
case of the compressor, as its operation is the opposite. The noise gate prevents the passing of
lower levels of the signal that could be considered noise. Therefore, the range of settings is
different. In addition, there is an additional parameter for noise gates, which is “Hold Time.” This
is a safety period used to prevent the gate from accidentally closing if a signal is suddenly
absent, for example, in speech.
In addition, the threshold must be adjusted to a level slightly higher than the level of the noise to
be avoided. Thus, the threshold will be set at a very low level. Above the threshold, the noise
gate does not act (unity gain), letting the rest of the signal through without processing it. The
gate remains closed; i.e. when the signal surpasses the threshold level, the gate opens. The
attack time is the time the gate takes to open (unity gain) when it receives a signal whose
amplitude exceeds the threshold level; this time must be short to avoid cutting off the beginning
of a sentence or song. The release time is the time the gate takes to close when the signal level
falls below the threshold. The hold time is the minimum time during which the gate remains
open; it is used to prevent the gate from closing when the signal level drops briefly—for
example, when an announcer pauses while speaking. The hold time prevents the gate from
opening and closing constantly in the presence of a signal whose level fluctuates in a range
close to the threshold level.