I've pretty much ruled out the doorbell "ding" because our apartment doesn't have a doorbell, but just a knocker. And I've checked the timer on both the microwave and that other big hot-box thing under the cooktop. The elevator down the hall makes a "ding" when it arrives at our floor, but it is much louder than the faint "ding" I'm talking about here.
It's aggravating the same way a smoke detector is when it's battery goes dead. Except that's always, always at 3 am, and it goes "chirp", not "ding". But nowadays with 6 or 8 smoke detectors in every home, finding the culprit is a hair-pulling exercise. I've even changed ALL the batteries at the same time, figuring that would absolutely shut the damn things up. But as it turns out, sometimes those things just go bad for no apparent reason and need to be replaced. *sigh*
In our humble abode we have two computers (his 'n hers), two iPads (his 'n hers), and two smartphones (his 'n hers), plus "her" has a couple of other electronic gizmos that might also make noises, too, I'm not sure. But right now, my guess is it's one of those contraptions.
But why would it "ding"? To notify me of something? But what? Wouldn't there be some sort of announcement on the screen? To tell me there's some new blog post or Facebook entry or email ready to read? Those things come and go all day long, and I get many more of those than I hear "dings".
Me and Luke out for a stroll.
Maybe I'm the unwilling participant in some sort of psychology experiment to find out "how many unexplained 'dings' does a man have to hear before he goes completely insane?" In which case they've got the wrong guy. Some say I passed that milestone years ago. ;)