This is driving me nuts. I have bluetooth in my car, the iphone is connected to it. If I am on a call, Navigon shouts the turns and this and that, I can not turn it off. The 'volume' slider in the app is all the way down, so when i am NOT using the phone via bluetooth the sound is off. However, when i am on a call, Navigon goes through the bluetooth and won't shutup! Is there no global TURN SOUND OFF? TIA.