Hi everyone. I have a 2004 300ci and just yesterday, I've been noticing a slight hissing sound from my speakers when I turn my key to the position where the stereo can be turned on but the engin is not on. The hissing sound is noticable even though the stereo is not turned on. Has anyone had this happen to their bmw before? I am going to have it checked out when I take mine in for the oil change.