10.6

364Logic Pro User Guide
Remove silent passages from audio files
Remove silent passages in a Logic Pro project
You can remove silent passages from audio regions in the Remove Silence window. The
basic process is simple:all amplitude values below a threshold level are removed, and new
regions are created from the remaining passages.
The parameters of the Remove Silence window are:
• Threshold: Use to define the amplitude level that a passage must exceed, in order to
be defined as a region. In terms of the number and length of regions created by the
process, this is the most important parameter. As a general rule:a higher Threshold
value leads to numerous short regions. Low values create fewer large regions.
• Minimum Time to accept as Silence: Use to define the length of time that a section must
be below the Threshold value, before it is considered a gap. Very small values tend to
increase the number of regions, because even short dips in amplitude are interpreted as
silence. Higher values prevent sections of audio from being interrupted by fluctuating
amplitudes.
• Pre Attack-Time: Use to add a defined amount of pre-roll to the beginning of all regions
created by the Remove Silence process. High threshold values prevent any amplitudes
with slower attack times from being chopped. This function is useful for nonpercussive
material such as vocals, wind instruments, strings, and so on. Overlaps are permitted—
the pre-delayed start point of a region can extend back to the end of the previous
region—but only if the Threshold value is not exceeded. The Pre Attack Time doesn’t
affect the anchor position, which means the absolute position of the audio data (in the
project) is retained.
• Post Release-Time: Use to define an automatic release time for the end points of all
regions, avoiding abrupt cutoffs to amplitudes that fade out gradually (particularly if you
have set a high Threshold value); for example, cymbals, open hi-hats, snares with long
reverb tails, vocals, and so on. This parameter does not allow overlaps, which means
that region end points cannot extend beyond the start point of the following region.
The Post Release Time doesn’t affect the anchor position, which means the absolute
position of the audio data (in the project) is retained.
• Search Zero Crossings: Select this checkbox to automatically snap the region start and
end points to the nearest waveform zero crossings.