Apple Logic Express 8 - Manual (Page 287)

Chapter 11 Adding Pre-Recorded Media 287
Overview Calculation
When you add an audio file to your project, Logic Express will automatically create an
overview of the audio file. This is a graphic file that is used to display the waveform.
The calculation of audio file overview data is shown in a window. This calculation
occurs in the background, allowing you to continue working with Logic Express.
Enabling the “Faster overview calculation” option considerably speeds up the
calculation, at the cost of slowing down other operations, but not blocking user
interaction completely. Logic Express remembers the state of the “Faster overview
calculation” option between projects.
You can manually refresh the overview of selected files with Options > Audio > Refresh
Overview(s) in situations where you have replaced file recordings (and used regions), or
made edits in an external sample editor.
Waveform overview