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Table Of Contents
36 Chapter 4 Dynamics
Some compressors, called multiband compressors, can divide the incoming signal into
different frequency bands, and apply different compression settings to each band. This
helps achieve the maximum level without introducing compression artifacts, and is
typically used on an overall project mix.
Expanders
Expanders are similar to compressors, except that they raise, rather than lower, the
signal when it exceeds the threshold. Expanders are used to enliven the audio signal.
Limiters
Limiters (also called peak limiters) work in a similar way to compressors, in that they
reduce the audio signal when it exceeds a set threshold. The difference is that while a
compressor gradually lowers the signal level above the threshold, a limiter quickly
reduces any signal louder than the threshold to the threshold level. The main use of a
limiter is to prevent clipping, while preserving the maximum overall signal level.
Noise Gates
Noise gates alter the signal in the opposite way that compressors or limiters do. While a
compressor lowers the level when the signal goes above the threshold, a noise gate
lowers the signal whenever it is below the threshold. Louder sounds pass through
unchanged, but softer sounds, such as ambient noise or the decay of a sustained
instrument, are cut off. Noise gates can be used to eliminate low-level noise or hum
from an audio signal.
The following sections describe the effects included with Logic Express.
 Compressor on page 37
 DeEsser on page 41
 Ducker on page 43
 Enveloper on page 45
 Expander on page 47
 Limiter on page 48
 Noise Gate on page 49
 Preset Multipressor on page 52
 Silver Compressor on page 53
 Silver Gate on page 54