I was not involved with much of the noise diagnosis at dealers. My hearing isn't good and it wasn't usually assigned to me, except exhaust leaks and engine noises. Sometimes the advisor would ask me to go ride with a customer to hear something, which was pointless, unless it was really loud.
I'm riding with a guy in a Volt and he says "there, do you hear that?" No, I didn't hear anything. He tells me his wife can't hear it either, nor can anyone else he's tried to demonstrate it to. WTF?