Apple Logic Pro 8 - Manual (Page 499)

Chapter 21 Editing Audio in the Sample Editor 499
Reversing the Selected Area of an Audio File
The Reverse command is most commonly used on an entire audio file, to reverse a
cymbal sound, for example. It can also be used as a creative option on selected
portions of audio files. As an example, the reverb tail at the end of a file can be
reversed, copied, and pasted to the beginning of the file.
To reverse the selected area of the audio file:
m Choose Functions > Reverse (or use the corresponding key command,
default: Shift-Control-R)
Trimming Audio Regions
You can use the Trim command to remove unimportant passages (generally silence)
from the start and end of your audio files. Trim can also be used to remove portions of
audio files that are not used by regions.
To erase all unselected portions of an audio file:
m Choose Functions > Trim (or use the corresponding key command: Control-T)
Important: Make sure that the areas you are about to delete do not contain any
regions that you may need. Regions outside the selection area will be lost. Portions of
regions that fall partly outside the selection area are also removed, resulting in a length
reduction of the region. If any such regions are being used in the Arrange area, a
warning dialog will give you the option of cancelling the trim command.
Normalizing Audio Files
Normalization is a process that raises the maximum level of a digital signal to a
specified amount—typically to its highest possible level, without introducing
distortion.
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Tip: The start and end points for the section being normalized should generally not fall
within a continuous section of audio, as this will result in abrupt increases in volume
after normalization. The start and end points should therefore be located in sections
that occur just after, or before, musical gaps.
To normalize the selected area in an audio file:
m Choose Functions > Normalize (or use the Normalize key command,
default: Control-N).
Logic Pro finds the point with the highest volume in the current selection area, and
determines how far this is from the maximum possible level. The level of the selected
area is then raised by this amount. The dynamic relationships of sample levels within
the audio passage remain unaltered.