Apple Logic Pro 8 - Manual (Page 473)

Chapter 20 Editing MIDI Events in the Transform Window 473
Velocity Limiter
Limits the velocity to a maximum value. This is perfect for transforming instrument
parts that are too strident, by limiting the velocity.
Change the Max operation field value to limit the velocity to a maximum value. This is
instantly reflected in the map area below.
Fixed Note Length
Creates constant note lengths. Useful on many instruments, particularly drums and
other rhythmic parts, such as pianos, clavinets, and basses.
Change the Length value field in the Operations area to change the lengths of all
selected events to the chosen length. Both shorter and longer events are changed to
match the length value you have defined.