Silver Gate is a simplified version of the Noise Gate plug-in. See Use Noise Gate.
Lookahead slider and field: Set how far ahead Silver Gate analyzes the incoming signal, allowing it to respond more quickly to peak levels.
Threshold slider and field: Set the threshold level. Signals that fall below the threshold are reduced in level.
Attack knob and field: Set the time it takes to fully open the gate after the signal exceeds the threshold.
Hold knob and field: Set the time the gate remains open after the signal falls below the threshold.
Release knob and field: Set the time it takes to fully close the gate after the signal falls below the threshold.