I have a MacBook Pro and last time I observed a strange behavior. When the fridge is turning on (to start cooling down again) I get a loud noise through the headphone jack on the external sound system. This also happens if the fridge is itself turning off (but not so loud as before).
I never experienced such behavior before on any of my devices (including PC). But I noticed this noise doesn't appear if I listen to music on the internal speakers of the laptop.
Has somebody an idea why this is happening and what I can do against this?