Apple Logic Pro 9 - Manual (Page 670)

Protecting the Position of Events in the Piano Roll Editor
There are times when you will want to protect certain events from being moved. For
example, several note events may be used to trigger footstep samples that match an
actor walking down a corridor, in a video soundtrack.
You have already created the music for this scene, but have been asked to increase the
tempo to match several cuts of different camera angles in the corridor. Obviously, a
change in the tempo will move the events, resulting in out-of-sync footstep samples.
Fortunately, Logic Pro has a feature that preserves the absolute time position of events.
To protect the position of one or more selected events
µ
Choose Functions > Lock SMPTE Position (or use the corresponding key command).
This ensures that events that fall at a particular absolute time position—1 hour, 3 minutes,
15 seconds, 12 frames, for example—remain at this position when tempo changes are
made.
To unprotect the position of one or more events
µ
Choose Functions > Unlock SMPTE Position (or use the corresponding key command).
Changing Note Velocity in the Piano Roll Editor
Note velocity is usually tied to the level of the note, and given the use of color to indicate
different velocities, you can quickly identify the “loud” and “soft” notes in a region.
Note: Velocity can also be used as a controller for other synthesizer parameters, such as
filter resonance or cutoff, either alone or in conjunction with level. As such, you may find
that changes to note velocity not only affect the level of the note, but also tonality.
To alter the velocity value of a note
µ
Drag a note vertically with the Velocity tool.
A help tag indicates the velocity value of the note you clicked, with the value changing
as you drag. The color of the note event changes and the horizontal line inside the event
either lengthens or shortens.
If the MIDI Out function is turned on (and it should be), the note is output as you alter
the velocity.
All selected notes can be altered simultaneously; the differences in their respective velocity
values are 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.
670 Chapter 23 Editing MIDI Events in the Piano Roll Editor