Analog TVs put off a high-pitched whine that apparently only dogs and I can hear. German analog TVs have a louder whine than American ones. When I lived in Germany as a kid, I could walk into a house and tell you if the TV was on even if the TV wasn't in my line of sight and the volume was muted.
My parents have a grandfather clock that used to keep me awake at night all the way on the other side of the house with my bedroom door shut.
cc @ZenHeathen