harry12345 wrote:
Here is my theory.
If a sound is travelling away from you the pitch goes lower, right? Doppler effect.
Well. If you think about it there must be millions of phones ringing around the world right now at this precise moment. Chances are more of them are moving away from you than towards you.
Add up the noise from all those phones ringing and dopplering to a lower frequency and there is your hum.
On the other hand it could just be distant traffic noise. The multitudinous thwack of vulcanised rubber on a pothole edges.
I don't think so otherwise it would be all the time or much more often. This noise comes, lasts a couple of months and then leaves. Then it comes back for a couple of months and leaves again. It stops for a long time, like several months to a year before it comes back again.
_________________
"I'm bad and that's good. I'll never be good and that's not bad. There's no one I'd rather be than me."
Wreck It Ralph