A) Find the total absorptivity of an empty room at 1,000 Hz. The room is 20 X 30 feet in plan and 10 feet high. The floor is concrete covered with carpet, one 20 foot wall is plate glass, and the other three (3) walls are half inch gypsum board over studs. (It is not unusual to disregard doors when calculating absorptivity, but they are most important when dealing with transmission). The ceiling is of smooth finished plaster on lath. What would be the absorptivity if we provided heavy drapes across the window in the example above? What would be the reduction in sound?