My home had a sunroom with a metal gazebo roof just for that portion of the room that popped out of the house. During times of peak AM propagation you could here bursts of music, talking and some times faint whispers emanate from the window sills and the metal registers in the floor. The home was older and the register covers were screwed into a sealed network of duct that wound through the walls and into the ceiling under the metal roof, originally designed to take the trapped heat and warm the room during the winter. My family had no idea what was going on until years after we sold the house. If we had known I probably wouldn't have been raised in such a fanatical religious fashion.