User Manual

Core Avid Audio Plug-Ins
971
Ratio Sets the compression ratio, or the amount of compression applied as the input signal
exceeds the threshold. For example, a 2:1 compression ratio means that a 2 dB
increase of level above the threshold produces a 1 db increase in output. Values
range from 1:1 (no compression) to 100:1 (hard limiting).
Limiting generally begins with the ratio set at 10:1 and higher. Large ratios
effectively limit the dynamic range of the signal to a specific value by setting an
absolute ceiling for the dynamic range.
Attack Sets the attack time, or the rate at which gain is reduced after the input signal
crosses the threshold. Values range from 10 microseconds (fastest attack time) to
300 milliseconds (slowest attack time).
The smaller the value, the faster the attack. The faster the attack, the more rapidly
the Compressor/Limiter applies attenuation to the signal. If you use fast attack
times, you should generally use a proportionally longer release time, particularly
with material that contains many peaks in close proximity.
To use compression most effectively, the attack time should be set so that signals
exceed the threshold level long enough to cause an increase in the average level.
This helps ensure that gain reduction does not decrease the overall volume too
drastically, or eliminate desired attack transients in the program material. Of course,
compression has many creative uses that break these rules.
Release Sets the length of time it takes for the Compressor/Limiter to be fully deactivated
after the input signal drops below the threshold. Values range from 5 milliseconds
(fastest release time) to 4 seconds (slowest release time).
Release times should be set long enough that if signal levels repeatedly rise above
the threshold, the gain reduction “recovers” smoothly. If the release time is too
short, the gain can rapidly fluctuate as the compressor repeatedly tries to recover
from the gain reduction. If the release time is too long, a loud section of the audio
material could cause gain reduction that continues through soft sections of program
material without recovering.
Gain Lets you boost overall output gain to compensate for heavily compressed or limited
signals. Values range from 0 dB (no gain boost) to +40 dB (loudest gain boost). 0
dB is the default value.
Threshold (THRESH) Sets the level that an input signal must exceed to trigger compression or limiting.
Signals that exceed this level will be compressed. Signals that are below it will be
unaffected. Values range approximately from -60 dB to 0 dB (no compression or
limiting). -24 dB is the default value.
In the Levels panel, the orange Threshold arrow on the Input meter indicates the
current threshold. You can drag the arrow up and down to adjust the Threshold
setting.
In the graph display, the threshold appears as an orange vertical line.
Parameter Description