Logic Pro X: Split chords in the Piano Roll Editor
The following functions let you divide chords by pitch and assign notes to different MIDI channels by pitch.
Select the top or bottom note of selected chords
Do one of the following:
Choose Edit > Select > Highest Notes from the Piano Roll Editor menu bar to select the highest notes in the chords.
Choose Edit > Select > Lowest Notes to select the lowest notes in the chords.
These commands can be used with regions containing chords to separate the top note of each chord (often the melody), or to separate the bottom note of each chord for a bass line. Once selected, the notes can be cut or copied, and pasted into a region on a different track.
Note: Highest Notes and Lowest Notes only select the notes. They can be used in conjunction with other editing commands, such as Cut, to move a voice into another MIDI region.
Assign notes to different MIDI channels by pitch
Select the notes you want to reassign by clicking keys on the keyboard along the left edge of the Piano Roll Editor.
Shift-click to select multiple keys.
Drag across the keyboard to select a range of contiguous pitches.
Choose Functions > Set MIDI Channel to Voice Number from the Piano Roll Editor menu bar.
Logic Pro assigns MIDI channel numbers (in ascending order) to individual note pitches in the selected MIDI region. The highest note pitch in each chord is assigned as MIDI channel 1, the next note down in each chord channel 2, and so on.
Note: The use of these commands results in changes to the MIDI region, which contains information spread across multiple MIDI channels, following the operation.
After using the Set MIDI Channel to Voice Number function, you can create a new MIDI region for each note by using the Edit > Separate MIDI Events > By Event Channel menu command in the Tracks area. Each region created from this process can then be assigned to a different track (and channel), allowing different instruments to be assigned for each voice.