Has anyone had this happen? I have the unit with the navigation system, and I have noticed that everytime I restart the car, the midrange is muted. If I flip to the audio controls and adjust the midrange (either up or down) the sound seems to pop and come alive. It helps to do this with music played a little on the louder side, but it is very noticeable on my system. Once I adjust the midrange, the sound remains normal until I cut the car off again.