I have had an HTC Rezound for about 18 months now and have had no problems. However, recently it has begun randomly beeping for no apparent reason. There are no notifications, no texts, no voice mail, nothing on the calendar, no Apps running and I have checked for every possible setting that might be causing this, but to no avail.
Looking back, it seems to have coincided with the installation of Android 4.05.605 which occurred on 05/02/13.
Another thought I had, is it possible that it beeps when switching between 1X and 3G, given that I live in a very rural area?