The formulas for constructive and destructive interference for sound waves are presented in the window below. The animation on the right illustrates how sound waves from two identical sound sources interfere with each other.
The interference demonstration is shown in the window below. The physics student is directed to select the location of a person in a room where two identical alarms are emitting sound waves. Based on the location of the selected person, the sound waves combine to produce full constructive interference, full destructive interference, or some intermediate form of interference. The sound produced by the combined sound waves may be played.