Apple Logic Pro 9 - Manual (Page 1255)

MIDI Meaning Settings
The settings in the MIDI Meaning pane determine if, and to what extent, the insertion of
the listed symbols affect the MIDI playback of notes (that these symbols are attached to).
The above symbols change the MIDI output of all notes they are attached to. Two
parameters can be determined for each symbol: velocity and length.
The MIDI Meaning functions are most useful when you’re inserting notes with the mouse.
This makes it possible to work as if writing music on paper.
• First, you write/insert the notes. They will all have the same velocity, and identical
rhythmic note values will have exactly the same length.
• Accents and phrasing marks are then attached to some of the notes, which changes
the velocity and (playback) length of these notes.
1255 Chapter 43 Project Settings in Logic Pro