Apple Logic Express 9 - Manual (Page 172)

Setting the Project Time Signature
The time signature defines how many beats a bar contains in the Bar ruler and what note
value constitutes one beat.
Time signatures do not affect the playback of your project, but determine the editing
grid in the Arrange area and MIDI editors as you can see in the following images. Both
show the same MIDI region, with the first at a time signature of 2/8, and the second at
6/8.
172 Chapter 7 Working with Projects