Apple Logic Pro 9 - Manual (Page 414)

No Mixdown Situation
If there are several regions (mono or stereo) in a row on the same track that have been
cut out of one region with the Scissors tool, no mixdown happens. In this situation, a
single region is created over the entire area. This delivers the desired result, without using
any additional disk space.
Note: Logic Pro can recognize associated regions, even if there are gaps between them.
The determining factor is that the relative position of the regions in the Arrange area
corresponds to the relative position of the regions in the underlying audio file.
No mixdown occurs when you try to mix two regions on tracks that are panned to opposite
sides, as the two resulting mixdown files would be identical to the original audio files (in
the areas used for the regions).
Genuine Mixdown with Clipscan
If you combine audio data (in regions) from two or more tracks, the current pan and
volume values for the individual tracks will define the pan and volume settings in the
new audio file.
If you want to combine both sides of a stereo audio file (a mono channel on each of two
tracks), first set the pan controls of the component mono sides to hard left and hard right,
respectively.
Following the digital clipping scan (Clipscan) and completion of the mixdown, Logic Pro
replaces the previously selected regions with one region that contains the entire
mixed-down audio file.
You can use the Edit > Undo function (Command-Z) to restore the original audio regions,
if you change your mind about the mixdown. If you do so, you are asked if you want to
keep, or delete, the newly created mixed audio file. If you keep it, it remains in the Audio
Bin, and can be further used and processed.
During a mixdown, the 32-Bit resolution Clipscan function ensures that the highest
possible level is maintained, without clipping.
Mixdown of Audio Regions on a Track
If several overlapping audio regions are selected on a single track, no mixdown occurs.
You are asked to create a new audio file, which is named after the first region on the
track. The selected regions are then mixed together, with no changes to volume, and
without clip scanning.
If there are empty sections between two regions, these are added into the new audio file
as silent passages.
Audio Crossfades in Digital Mixdown
The Digital Mixdown supports crossfades between selected regions.
414 Chapter 13 Creating Your Arrangement