I just purchased an iPhone dock for iP4, and don't know if the following is normal, or if it's a defect: Whenever I plug the phone in to the dock, I can't hear unlock or shut down sounds. The audio doesn't play in the Music app. When I try to raise or lower the volume, the incrementing boxes aren't showing. The only time the sound works is when I'm getting an incoming call. edit: Just checked Line Out, and the sounds work through headphones only.. Guess it's defective then?