Adobe AUDITION 3 User Manual page 155

To achieve the best results with the Noise Reduction effect, apply it to 16- or 32-bit audio with no DC offset. With
8-bit audio, this effect cannot reduce noise below -45 dB, which is very audible. (To achieve a lower noise floor with
8-bit audio, upsample the file to 16 bits, apply the Noise Reduction effect, and downsample the file back to 8 bits.)
With a DC offset, this effect may introduce clicks in quiet passages. (To remove a DC offset, select the Center Wave
preset provided by the Amplify/Fade effect.)
A
B
Adjusting frequency-specific settings with the Noise Reduction graphs
A. Noise floor B. Reduction graph C. Original audio D. Processed audio
To reduce noise added by a sound card during recording, start the recording with a second of silence. After recording
is complete, use that silence as the Noise Reduction Profile, and then remove it from the complete recording. In some
cases, this process can increase dynamic range by 10 dB.
See also
"About process effects" on page 104
"Control effects settings with graphs" on page 104
Apply the Noise Reduction effect
In Edit View, select a range that contains only noise and is at least half a second long.
1
To select noise in a specific frequency range, use the Marquee Selection tool. (See "Select spectral ranges" on page 73.)
Choose Effects > Restoration > Capture Noise Reduction Profile.
2
In the Main panel, select the range from which you want to remove noise.
3
4 Choose Effects > Restoration > Noise Reduction.
Set the desired options.
5
Noise Reduction options
Displays either the left or right channel noise profile. The amount of noise reduction is always the same for
View
both channels. To perform separate levels of reduction on each channel, edit the channels individually.
Represents, in yellow, the amount of noise reduction that will occur at any particular frequency.
Noise Profile graph
Adjust the graph by moving the Noise Reduction Level slider.
Extracts a noise profile from a selected range, indicating only background noise. Adobe Audition
Capture Profile
gathers statistical information about the background noise so it can remove it from the remainder of the waveform.
C
D
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