Curiously I can tell if 120VAC 60Hz wiring circuit in the wall is on or not. My guess is it's more sensing the EMF from the wiring than actual sound noise. If the wire is hot even if nothing is plugged into the socket, it causes me to be tense all the time. No power to the circuit and I'm a lot more relaxed. When I'm not sleeping good, I will often flip the breakers to knock out power in the bedroom area. If I shut the power down or it goes out on it's own, the stress level that I didn't realize was there drops way off within seconds.
Speaking of which, I really have to disable that annoying 120V socket and wiring that runs under my bed soon before it makes me nuts. I'm already seriously considering a rewiring/breaker adding session this summer to have hot 120V wires running only where and when they're needed.