Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 5.00 m. a person is standing 12.0 m away from the wall, equidistant from the loudspeakers. when the person moves 1.00 m parallel to the wall, she experiences destructive interference for the first time. what is the frequency of the sound? the speed of sound in air is 343 m/s.