Im on my 2nd replacement already and there seem to be a distinct tapping noise as if there is a helicopter flying over your head constantly. The first Gopro I got did the same thing.  This ONLY occurs in the wifi mode paired with my HTC1 phone when press recording on the phone . I've heard other stories as well and seem to be happening to alot of people.  If you bass fish we know we need that wifi.  Going to get it exchange for the 3rd time see how that goes.  If no good refund and wait till they fix the bugs and settle for less on craigslist.

It's not your Gopro.  You have black ops helecopters circling you.