Select Lowest Notes ⇧↓ — Logic Pro keyboard command of the day

  Select Lowest Notes    ⇧↓

Select the lowest notes in each chord. From here the notes can be assigned to a different MIDI channel, instrument, etc.

Split chords in the Piano Roll Editor — Logic Pro X

Choose Edit > Select > Lowest Notes to select the lowest notes in the chords.

Split chords in the Piano Roll Editor in Logic Pro — Apple Support

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.

Voice Separation Tool J — Logic Pro X keyboard command of the day

Shows the Voice Separation tool in action
  Voice Separation Tool  J

Switch the selected tool to the Voice Separation Tool. This tool is only available in the Tool Menu in the Piano Roll and Score Editor. The legend in the Tool menu does not show a J, it shows an up-arrow over a down-arrow.

NB the T command shows the Tool menu except when Logic first starts. You have to click on the Tool menu with the pointer before the T command becomes active. This, I think, is a bug.

Assign notes to voices and staffs in Logic Pro — Apple Support

Using the Voice Separation tool, you can draw a separation line between notes on a staff to assign them to the predefined MIDI channels of the voices.

Assign notes to voices and staffs in Logic Pro — Apple Support

Select the Voice Separation tool, then draw a line (between notes) where you want to separate the voices.

View Mode: Selected Regions — Logic Pro X keyboard command of the day

  View Mode: Selected Regions

Set the piano roll to show notes/events from the selected regions as opposed to the focused track. The vertical line showing the MIDI regions is very useful. Who said all MIDI regions had to be the same color?

The control of the view is in the “View” menu of the Piano Roll.

View multiple regions in the Piano Roll Editor in Logic Pro — Apple Support

Notes from all of the selected regions appear in the Piano Roll Editor. The start point of each MIDI region is indicated by a vertical line of the same color as the MIDI region itself.

Trim Note to Remove Overlaps for Adjacent \ — Logic Pro X keyboard command of the day

  Trim Note to Remove Overlaps for Adjacent  \

Shortens a note to prevent _interference_ with other notes. A simple example would be a note being played for an entire beat plus a bit more. When converting these notes to a score you could get interesting forms of ties and rests. This cleans thing up so the notation (and potentially _voice stealing_ from a MIDI device) will be clear and concise.

Resize notes in the Piano Roll Editor in Logic Pro — Apple Support

There are a number of commands in the Edit > Trim submenu in the Piano Roll Editor menu bar to change the length of selected notes, in relation to notes surrounding or overlapping them. They can be very useful for tidying up the start and end points of notes.

Set Finger Tool ⌥8⃣ — Logic Pro X keyboard command of the day

resize event
  Set Finger Tool        ⌥8⃣

Use the Finger Tool to change the length of events in the Piano Roll, or move steps in the Step Editor.

Only visible in the Tool Menu for the Piano Roll and Step Editor. Keyboard quick access is ‘T’-‘F’

Resize notes in the Piano Roll Editor in Logic Pro — Apple Support

You can resize notes in the Piano Roll Editor to change their length (duration). Notes can be resized from either their start or end point using the Pointer, Finger, or Pencil tool.