Apple Logic Pro 9 - Manual (Page 1162)

Setting the Surround Preferences
The I/O Assignments tab features three sub-tabs: Output, Bounce Extensions, and Input.
All three tabs are linked, but can be adjusted independently.
Note: As a general rule, the default settings for each surround format should meet your
needs in all but the rarest circumstances.
To set the surround channel assignment
1 Click either the Output or Input tab.
1162 Chapter 39 Working with Surround