Adobe AUDITION 3 User Manual page 125

Set the input level at which compression begins. Possible values range from -60 to 0 dB. The best
Threshold sliders
setting depends on audio content and musical style. To compress only extreme peaks and retain more dynamic range,
try thresholds around 5 dB below the peak input level; to highly compress audio and greatly reduce dynamic range,
try settings around 15 dB below the peak input level.
Measure input amplitude. Double-click the meters to reset peak and clip indicators.
Input Level meters
Measure amplitude reduction with red meters that extend from top (minimal reduction) to
Gain Reduction meters
bottom (maximum reduction).
Boosts or cuts amplitude after compression. Possible values range from -18 to +18 dB, where 0 is unity gain.
Gain
Sets a compression ratio between 1-to-1 and 30-to-1. For example, a setting of 3.0 outputs 1 dB for every 3 dB
Ratio
increase above the compression threshold. Typical settings range from 2.0 to 5.0; higher settings produce the
extremely compressed sound often heard in pop music.
Determines how quickly compression is applied when audio exceeds the threshold. Possible values range
Attack
from 0 to 500 milliseconds. The default, 10 milliseconds, works well for a wide range of audio. Faster settings may
work better for audio with fast transients, but such settings sound unnatural for less percussive audio.
Determines how quickly compression stops after audio drops below the threshold. Possible values range
Release
from 0 to 5000 milliseconds. The default, 100 milliseconds, works well for a wide range of audio. Try faster settings
for audio with fast transients, and slower settings for less percussive audio.
Boosts or cuts overall output level after compression. Possible values range from -18 to +18 dB, where
Output Gain
0 is unity gain. Double-click the meters to reset peak and clip indicators.
Applies limiting after Output Gain, at the end of the signal path, optimizing overall levels. Specify Threshold,
Limiter
Attack, and Release settings that are less agressive than similar band-specific settings. Then specify a Margin setting
to determine the absolute ceiling relative to 0 dBFS.
To create extremely compressed audio, enable the Limiter, and then experiment with very high Output Gain settings.
Displays the frequency spectrum of the input signal, rather than the output signal, in the
Spectrum On Input
multiband graph. To quickly see the amount of compression applied to each band, toggle this option on and off.
Applies immediate, hard limiting at the current Margin setting. (Deselect this option to apply
Brickwall Limiter
slower soft limiting, which sounds smoother but may exceed the Margin setting.)
Note: The maximum Attack time for brickwall limiting is 5 ms.
Lets you globally adjust the compression settings for all bands, while retaining relative differ-
Link Band Controls
ences between bands.
To temporarily link band controls, hold down Alt+Shift. To reset a control in all bands, hold down Ctrl+Alt+Shift,
and click the control.
Normalize effect (Edit View only)
The Amplitude And Compression > Normalize effect lets you set a peak level for a file or selection. When you
normalize audio to 100%, you achieve the maximum amplitude that digital audio allows—0 dBFS. If you're sending
audio to a mastering engineer, however, normalize audio between –1 and –4 dBFS, providing a cushion for further
processing.
The Normalize effect amplifies the entire file or selection equally. For example, if the original audio reaches a loud
peak of 80% and a quiet low of 20%, normalizing to 100% amplifies the loud peak to 100% and the quiet low to 40%.
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User Guide