I've been hearing this low pitched hum in my area of Melbourne for the last two weeks. It's been driving me nuts. To me it's not even subtle. but no one else seems to hear it.
They've cranked it up to day, I can feel it right through my body. Like I'll wake up thinking my heart's racing, then realise that's not my heart, that's the machine again. It's an irregular heart beat that speeds up and slows down.
The other thing about this hum is it's really hard to find where it's coming from. It's really loud inside, especially a small room, because it's resonating off the glass and the walls. But when I go outside it's hard to track down. I can hear it in my car but not when the engine's running.