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Dynamics processors overview
Dynamics processors control the perceived loudness of your audio, add focus and punch to
tracks and projects, and optimize the sound for playback in dierent situations.
The dynamic range of an audio signal is the range between the softest and loudest parts of the
signal—technically, between the lowest and highest amplitudes. Dynamics processors enable
you to adjust the dynamic range of individual audio les, tracks, or an overall project. This can be
to increase the perceived loudness or to highlight the most important sounds, while ensuring
that softer sounds are not lost in the mix.
There are four types of dynamics processors. These are each used for dierent audio
processing tasks.
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Compressors: Downward compressors behave like an automatic volume control, lowering the
volume whenever it rises above a certain level, called the threshold.
By reducing the highest parts of the signal, called peaks, a compressor raises the overall level
of the signal, increasing the perceived volume. This gives the signal more focus by making
the louder (foreground) parts stand out, while keeping the softer background parts from
becoming inaudible. Compression also tends to make sounds tighter or punchier because
transients are emphasized, depending on attack and release settings, and because the
maximum volume is reached more swiftly.
In addition, compression can make a project sound better when played back in dierent audio
environments. For example, the speakers of a television or in a car typically have a narrower
dynamic range than the sound system in a cinema. Compressing the overall mix can help
make the sound fuller and clearer in lower-delity playback situations.
Compressors are typically used on vocal tracks to make the singing prominent in an overall
mix. They are also commonly used on music and sound eect tracks, but they are rarely used
on ambience tracks.
Some compressors—multiband compressors—can divide the incoming signal into dierent
frequency bands and apply dierent compression settings to each band. This helps to achieve
the maximum level without introducing compression artifacts. Multiband compression is
typically used on an overall mix.
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Expanders: Expanders are similar to compressors, except that they raise, rather than lower, the
signal when it exceeds the threshold. Expanders are used to add life to audio signals.
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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 dierence is that whereas a
compressor gradually lowers signal levels that exceed the threshold, a limiter quickly reduces
any signal that is 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.
Dynamics processors
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