Our old Tri girl, Daisy, tries to attack the toaster oven when it beeps... or the coffee-grinder when it goes... or the blender... or really, any kitchen-appliance that makes a noise. Before my parents remodeled their house, there was a little bathroom right off the kitchen - the funny thing was, if you just put Daisy in there before you ran the blender etc., she wouldn't make a peep. I'm sure she could hear the sound, but just having the door between her and the offending appliance was always enough!
We try to nip any ballistic-barking-at-common-stimuli in the bud at our house, because even if it starts as only one dog's neurosis, they'll quickly teach the behavior to the rest... and it's not much fun to have eight Shelties come flying into the kitchen in full attack-mode every time the toaster dings!