Control transposition with the Pitch Source parameter in Logic Pro for Mac
In Logic Pro for Mac 11 you can control the transposition of regions and loops in a project using the Pitch Source parameter in the Region inspector. Different region types have different Pitch Source options, including following key signature changes, following the chords on the global Chord track, or following region chords.
The available options in the Pitch Source pop-up menu are:
Off: The region does not respond to the key signature or to chords.
By setting Pitch Source to Off you can always return the region or loop to the original key in which it was recorded.
Key Signature: The region changes to match the project key, and changes with subsequent key signature changes.
Region Chords: The region follows any region chords it contains.
Chord Track: The region follows the chords on the Chord track.
For projects created in earlier versions of Logic Pro, there is an additional option for some region types:
Project Key: The region changes to match the project key, but not subsequent key signature changes.
This option is available for MIDI regions, MIDI Apple Loops, and audio Apple Loops in projects created in earlier versions of Logic Pro.
Regions
Audio regions have no Pitch Source setting and do not change with the key signature. MIDI regions and pattern regions are set to Off by default, but can be set to follow key signature changes. Session Player regions can either follow the Chord track or their region chords.
When the Pitch Source parameter for a Session Player region is set to Chord Track in the Region inspector, the region follows the Chord track; when set to Region Chords, the region follows its region chords. Changing the Pitch Source parameter changes which item is selected in the Chords menu, and vice versa.
Apple Loops
Audio, MIDI, and pattern Apple Loops with a key signature (indicated in the Loop Browser by a Chord icon 
) are set to Key Signature by default, while loops with no key signature (drums, percussion, and other non-pitched loops) are set to Off by default. Session Player Apple Loops can be set to follow either their region chords or the Chord track.
When you add an Apple Loop from the Loop Browser, it follows the selected Loop Chords option in the Loop Browser More menu:
Keep Region Chords: The loop follows the region chords it contains.
Replace Global Chords with Region Chords: The region chords in the loop are pasted to the Chord track at the position where you drag the loop.
Automatic: If there are no chords on the Chord track at the position where you drag the loop, the region chords in the loop are added to the Chord track at that position. If chords already exist on the Chord track at the position where you drag the loop, the loop follows its region chords. Session Player loops are an exception; If chords exist on the Chord track, they follow chords on the Chord track.
The Pitch Source parameter replaces the Transposition track used in earlier versions of Logic Pro. When you open a project created in an earlier version of Logic Pro, the Transposition track is still available.