I think the SXM suggestion may be on the right track. I also never use SXM but based on the prior comments I went to the music tab and hit the SXM button. I then heard the same chime and a pop up appeared saying something like “your free trial has started, press the Listen Now button to accept the user agreement”. I did not do so because I don’t plan to use it. I then toggled back to radio and the back to SXM several times and heard the chime and see the pop up each time. I wonder if that pop up is coming up in the background but not visible if not on the SXM screen but we still hear the chime. Maybe those who don’t hear it already accepted the SXM user agreement?