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. (Logic Pro does not support split surround files).