Apple Logic Pro 7 - Manual (Page 190)

190 Chapter 4 Audio in the Arrange Window
Split Stereo Regions are indicated by a stereo symbol consisting of two adjoining
circles (see right image above).
You can freely mix both formats, even on the same track. We recommend that you use
the Interleaved Stereo format if your audio hardware supports it.
Split Stereo files require around twice the hard disk I/O performance of Mono files.
Interleaved Stereo files, by comparison, only require about one and a half times the
throughput of Mono files.
You can check Force record & convert interleaved into split stereo files (force Logic to
create Split Stereo files) in Preferences > Audio > General, for compatibility with ProTools
(or other) systems.
Functions
Automatic Tempo Matching
Logic offers an automatic function that matches the length of a free-form musical
passage with the length of an audio Region. The length of the Region remains
constant, but the sequencer tempo is varied automatically, with the Region and
musical passage ending up exactly the same length.
To illustrate the use of this function, we’ll use a one-bar drum loop as an example:
Imagine you’ve recorded a drum loop live, or imported it from a sampling CD. You’ve
used the Audio window and Sample Editor to adjust the start and endpoints of the
audio Region, ensuring that the loop cycles perfectly, without any glitches.
Now, drag the drum loop into the Arrange window, where it appears as a Region. Make
sure that you place the front (left) edge of the Region at the start of a bar.
Construct a Cycle in the Arrange window Bar Ruler. Set the length to match the
intended musical length of the Region. The drum loop is one bar long, so you should
set a Cycle length of one bar, to match.
Once the Cycle is set to the desired musical length in the Bar Ruler, you’ll note that the
current length of the Region will be different to that of the Cycle.
Select Options > Tempo > Adjust Tempo using Region Length and Locators. The default
key command is “T”.