So the Prommers, are quite literally the people who stand to listen to the concerts. And there is space for about 800 people, right in the middle of the hall.
An empty chair stood in the very center of the room. There was something about the chair that gave Harry an ominous feeling. Chains encircled the arms of it, as though its occupants were usually tied to it.
Right in the very middle stood a huge shape like a man, but as tall as a tree, with a fierce face and a shaggy beard and a great club in its right hand.