I have a story about a high pitched whine.
I heard it about 3:00 AM when everything was quiet. It wasn't a smoke dete ctor's beep, but could have been one malfunctioning and whining very quietl y, or something similar.
I searched the whole house. The whine was everywhere, but impossible to lo cate. But it was much louder near the ceilings, which were hard plaster (o lder house). Yes, I got the ladder out and checked all the rooms.
So, climb into the attic, which was unfinished and had loose fill insulatio n, no noise. How can this be? Louder near the ceiling, but nothing in the attic?
Maybe it's coming in from outside. Nope. (quiet neighborhood, no traffic at all that time of night)
So I repeated the search several times, climbing ladders, going into the at tic, going outside and scratching my head, same results. Tired as I was, I couldn't let it go, couldn't think of anything else to try except keep doi ng the same thing that wasn't working.
Did I mention I'm right handed? I have a couple left handed kids but I am strongly right handed.
So when I'm standing outside thinking about it, I'm scratching my head with the right hand. And wondering why there is zero noise outside.
AND THEN: I scratch my head with my left hand. EUREKA! My digital watch had malfunctioned and was emitting the tiniest whine, impossible to locate but easy to hear in the dead quiet of night, especially when reflected by a hard plaster ceiling, and easily absorbed in the attic or outside.