My third mini, but my first 3rd gen. Picked up a F57 "S" w/ 24k miles. My wife claims there is a single thump that comes out of the center speaker on occasion. I have yet to hear it. She swears it is in the speaker and not the common rear suspension linkage. Is it possibly part of the "experience" and telling her something? Kinda like the ring making colors based on the function? Still trying to figure the quirks on this one, but its definitely my absolute favorite one so far!