Apple Logic Pro 9 - Manual (Page 477)

The Space bar provides a Sustain function—played with your thumbs rather than your
feet. You can trigger new notes or switch between octave or velocity values while notes
are sustained.
The current octave and velocity values of MIDI notes are displayed at the upper edge of
the Caps Lock Keyboard window. A Transparency fader is also available for this window,
making visualization clearer or allowing the window to be “ghosted” over the background.
Caps Lock Keyboard Preferences
The “Enable Caps Lock keys” option allows you to completely enable or disable the Caps
Lock Keyboard functionality.
If you want to use the Space bar to start, stop, or continue Logic Pro playback—rather
than as the Sustain function for the Caps Lock Keyboard (when active)—you can deselect
the “Space bar acts as sustain pedal” option.
Additional Caps Lock Keyboard Information
Due to technical limitations of computer keyboards, you can play a maximum number
of six notes simultaneously, and there are additional limitations regarding timing precision
and playing certain unusual note clusters.
The original intention of this feature, however, was to be a useful aid for composing on
a train or plane—not a full-on replacement for a real MIDI keyboard.
477 Chapter 14 Recording in Logic Pro