GarageBand '11: Split and join regions
You can join multiple regions from Real Instrument recordings (purple) into a single region, and join multiple Software Instrument regions into a single region. Regions from Real Instrument loops (blue), and Real Instrument regions that have been transposed can’t be joined.
To split a region:
In the timeline, select the region you want to split.
Move the playhead over the point in the region where you want to split it.
Choose Edit > Split, or press Command-T.
The selected region is split into two regions at the position of the playhead. Only the selected region is split, even if a region in another track is under the playhead as well. If multiple regions are selected and are under the playhead, they are all split.
When you split a Software Instrument region, any notes at the split point are shortened to that point.
To join regions:
Select the regions.
Choose Edit > Join, or press Command-J.
To be joined, Real Instrument regions must be adjacent to each other on the same track. Software Instrument regions must be on the same track or on adjacent tracks.
If you join segments of compressed audio files, the files are converted to AIFF format.