I haven't had a cabin over the buffet, but remember noise usually travels down, not up. When still a TA I had a cliant one time that was assigned a cabin on the Sea above the disco. They were worried sick, but on their return called to say the cruise was wonderful and they heard absolutely no noise. When we stay in some hotels if there are parties by the pools or late night music we very rarely hear much and that's with windows open. I don't think I would worry too much. You may hear a little, but nothing bad.