Does your Z4 do this? When you go to start the car, does the very first click of the key produce an audible pop through the speakers? Also after turning the engine off, that very last turn of the key (the one that lets you pull the key out)is there once again an audible pop through the speakers? It doesn't really matter if the audio system is left on or off for this to happen.
I'm thinking the pop I hear is the amp turning on and then it's the amp turning off. Maybe the amp is always activated but the preamp only comes on when you hit the on button. :?
I'm thinking the pop I hear is the amp turning on and then it's the amp turning off. Maybe the amp is always activated but the preamp only comes on when you hit the on button. :?