That’s going to leave a mark.
Seriously. I heard a sound like vacuum cleaner from the floor below. Kept getting louder and louder. Finally went upstairs and it was the USAF band. Not sure what they were doing, but they were dispersed throughout the floor and maintaining a note for an extreme time. Never did hear them play a tune, though I feel sure they did at some time.
Some kind of a gimmick; pretty cool.