I have a clip of audio in Garageband and what I want to do is cut the last 10 seconds off and then save the file as an MP3 (the whole clip is only 30 seconds). So I figured out how to delete the 10 seconds, but then when I export the clip, I still have a 30 second audio file, except that the last 10 seconds are just empty noise. How do I actually reduce the time of a Garageband track?