[arparent]

Have you tried going to the volume slider on the today screen and turning them back up? I beleive that the mogul retains certain 'volume profiles' depending on its state with bluetooth. It assumes that when you are using bluetooth, that you do not need system sounds because you can hear everything you need to hear in the headset. If you adjust the volume back up, maybe it will 'remember' that last state of volume and go back to it whenever it connects to bluetooth.