Here's the scenario. Google maps is navigating me to my destination. Pandora is playing music. The Razr Maxx is plugged inline to my car radio so the music and directions are coming over my car speakers. I take a phone call and Pandora goes mute but google maps keeps talking during my phone call. Even if I disconnect from the car radio and hold the phone to my ear, google navigation keeps talking. How do I shut up Google navigation while I am on the phone?