Apple Logic Express 8 - Manual (Page 431)

Chapter 16 Editing MIDI Events in the Piano Roll Editor 431
All selected notes can be altered simultaneously; the differences in their respective
velocity values will be retained. If the velocity value of any of the selected notes
reaches an extreme value (0 or 127), none of the other selected notes can be adjusted
further.
You can override this behavior by holding Option while dragging. This allows you to
continue altering the velocity values until the selected (clicked) note reaches an
extreme value. It goes without saying that this will alter the velocity relationship of this
note to the other notes.
To assign the same velocity value to all selected notes:
m Hold down Option-Shift while dragging on one of the notes with the Velocity tool.
Muting Notes
The Piano Roll Editor features a Mute tool that allows specific notes in a MIDI region to
be muted.
To mute/unmute a note:
m Click the note with the Mute tool.
Muted notes are grayed out (shown without color).
To mute or unmute all notes of a particular pitch in a MIDI region:
m Click on a piano key to the left of the Piano Roll Editor with the Mute tool.
This will mute or unmute all notes of that particular pitch, which is ideal for muting the
high-hats in a MIDI region that is triggering an entire drum kit, for example.
To mute or unmute multiple notes:
m Select the desired notes, then click one of the selected notes with the Mute tool
The Select Muted Regions/Events key command is also available in the Piano Roll
Editor. It allows the selection of all muted notes in a MIDI region. The next logical
operation would be to delete these muted notes by pressing Backspace.