Apple Logic Express 7 - Manual (Page 30)

30 Chapter 4 Dynamic
Silver Compressor
The Silver Compressor is a simplified version of the Compressor. It is limited to
Threshold, Attack, Release, and Ratio controls.
Noise Gate
Ordinarily, a noise gate suppresses unwanted noise that may become audible during a
lull in the signal. You can, however, also use it as a creative sound-sculpting tool.
Here’s the basic principle behind a noise gate: Signals that lie above the Threshold are
allowed to pass unimpeded (open gate). Anything below the defined Threshold
(background noise, crosstalk from other signal sources and so on) is fully muted (a
closed gate). In other words, the Threshold slider determines the lowest level that a
signal must be at, in order to open the gate—it separates the wanted or useful signal,
from the unwanted or noise signal.
The Reduction slider allows you to control the intensity of noise suppression. As a rule,
you should set it to the lowest possible value and leave it there, to ensure that the gate
closes completely. If you prefer, you can select other values, thus reducing the noise
signal less dramatically. As an alternative, you can actually boost the signal by up to
20 dB.