Every now and then on my iPad 2 I have this problem where sound stops coming out of the speakers. Mute is not turned on and volume is turned all the way up but no sounds are heard. I go into settings but the volume is all the way up, still no sound. However I turn it down using the screen slider in settings>sound and i start to hear the ringtone. i home button out of it, open an app, and still no sound. i have to reboot the ipad 2 in order to get sound restored. any ideas? this happened with 4.3.1 and now with 4.3.2 that i just upgraded to today.