This is the first I've heard of others having the same experience as
I. I'm amazed that I'm not the only one...I thought it was something
peculiar about myself.
I live in the Oakland, California hills, and my home is about 100
yards away from some high-tension transmission wires and towers. I've
tried to go outside when I hear the hum, but there's too much ambient
noise (wind in the trees, etc.) to hear it outside.
It doesn't wake me up, but sometimes it's so loud I do have trouble
going to sleep. I've done what others have reported: gone from room
to room, and so on. Of course, I've never localized it.
Must also say that I suffer from some high-frequency hearing loss,
which accentuates what comes through in the lower frequencies, and my
hum seems to be somewhere around the 40-60 cycle range. Haven't got a
frequency generator (any more, I used to before I got the hum), so
can't really compare. If anyone knows of a website which can generate
hums, that'd be useful.