Don’t know about white noise, but I had a cat who learned how to turn on the TV, and would do so before napping after that. I think it was more the heat that the TV gave off then the noise however, as he would nap ontop of the TV.
One of my cats likes to sit on the air filter, which also makes white noise. I’m not sure if she likes the noise, the breeze, the vibration, or all three.
My brother got a CD with a thunderstorm on it. Our cat would stare distrustfully at the stereo speakers when the thunder took place. She understood that it was thunder, which she didn’t like, but wasn’t quite sure why the sound came out of the speaker.
We had a kitty who liked to snooze on top of the TV set. Then she discovered hockey, and as she lay on top and looking down at the screen, would try catch the players or the puck with one of her paws. Cute as hell.