hey everybody. i'm having some issues recording in garage band which should hopefully be easy to clear up. i record an instrumental track into garage band through the line-in jack in the back. the track shows up in garage band just fine and plays, but i'm running into trouble recording while that track is playing. i plug my headphones in so i can try to hear the track while i am recording vocals, but i am unable to hear the track. i checked the inputs/outputs in system preferences and output is set to headphones, microphone is set to line in. so i'm not too sure what it could be. thanks! i have the '09 mac pro, 2.66 ghz quad core, using 10.6.2 i've tried recording on my girlfriend's imac, which is also running 10.6.2 and it works great.