Apple Soundtrack Pro - Manual (Page 168)

168 Chapter 7 Working in the Waveform Editor
Reducing Noise
Some audio files contain unwanted noise, making it difficult to hear the voices, music,
or other content of the file. Soundtrack Pro features two commands, Set Noise Print
and Reduce Noise, that you can use together to reduce noise in an audio file or
selection.
Set Noise Print
The Set Noise Print command lets you select part of an audio file containing only the
noise that you want to remove as a “noise print.” The noise print provides a signature of
the frequencies to reduce or remove from the file.
Setting the noise print before reducing noise is optional. If you do not set a noise print
before using the Reduce Noise command, Soundtrack Pro will extract a noise print
from the selected part of the audio file.
To set part of an audio file as a noise print:
1 In the waveform display, select the part of the audio file containing only the noise you
want to reduce.
2 Choose Process > Set Noise Print.
The selected noise is stored as a noise print.
Reduce Noise
The Reduce Noise command uses the frequency content of the noise print to reduce
noise in the audio file or selection.
To reduce noise using the noise print:
1 In the waveform display, select the part of the audio file in which you want to reduce
noise.
2 Choose Process > Reduce Noise.
The Reduce Noise dialog appears. In the Reduce Noise dialog, you can optionally set
the noise threshold and tone for noise reduction. You can also preview the noise
reduction with the dialog open.
The noise threshold determines the level below which audio in the noise print is
considered to be noise. Lowering the threshold results in only very low signals being
reduced, while raising the threshold results in more high level signals being reduced.