I stayed on the 33rd floor, and the rooms at least...

I stayed on the 33rd floor, and the rooms at least 3 of them as we had multiple for our group had a constant whirring sound that was clearly audible at all hours of the day and night. It sounded like perhaps the mechanics of the elevators (?); I'm not sure. It wasn't a significant annoyance, but still an annoyance. Otherwise, the hotel rooms were nice and clean.