synching with garageband

Still having trouble getting a recorded digital track to synch with an analog music track I've imported from iTunes. I know how to line them up using a sharp sound; and that seems to work okay visually, i.e. precisely, as far as I can see. But the audio isn't quite right. Is there a delay in the system that's different for analog and digital? Any suggestions? Or maybe I'm missing something simple. Thanks. Bobbo