Doorway Diffraction Sound of frequency 1250Hz leaves a room through a 1.0 D-m-wide doorway (see Exercise 36.5). At which angles relative to the centerline perpendicular to the doorway will someone outside the room hear no sound? Use 344 m/s for the speed of sound in air and assume that the source and listener are both far enough from the doorway for Fraunbofer diffraction to apply. You can ignore effects of reflections.