Apple Logic Pro 9 - Manual (Page 1203)

You can store multi-channel audio as interleaved or split channel audio files.
An interleaved audio file contains all channel information, stored in an alternating single
“stream.”For stereo files, this would be left channel, right channel, left, right, and so on.
For surround files, this would be channel 1, channel 2, channel 3, and so on, then back
to channel 1. Put into the context of a 5.1 surround mix: left, center, right, left surround,
right surround, LFE (then back to left, center, and so on) in a 6 channel interleaved file.
Split channel audio files couple separate audio files, allowing you to deal with each channel
(file) independently. For stereo files, two separate files are created, where one file contains
the left channel samples, and the other file contains the right channel samples. The files
are generally identified by a .L and .R suffix. The two files are linked, and are edited as a
pair. You can, however, disconnect them (in the Audio Bin), allowing each to be handled
independently. For multi mono (or split surround) files, multiple mono files are
created: one for each surround channel. As with split stereo, each file is identified by a
suffix. This is commonly as follows for a 5.1 surround mix: .L, .C, .R, .Ls, .Rs, and .LFE. Each
file is independent.
Logic Pro, and most other audio applications, support the import and recording of
interleaved files when using Core Audio hardware.
A handful of audio applications (including Pro Tools) only support split file formats, and
will automatically separate interleaved files when you import them. This is also true of
Logic Pro when importing interleaved stereo files using DAE/TDM hardware (Logic Pro
does not support split surround files).
Tip: You should use interleaved audio files if your audio hardware supports them. Split
channel audio files require significantly more hard disk I/O performance.
This chapter covers the following:
• Importing Split Channel Files (p. 1204)
• Working with Split Stereo Files (p. 1204)
• Exporting Split Channel Files (p. 1205)
1203
Working with Split Channel Audio
File Formats 42