A pair of speakers separated by 0.700 m is driven by the same oscillator at a frequency of 662 Hz.

A pair of speakers separated by 0.700 m is driven by the same oscillator at a frequency of 662 Hz. An observer, originally positioned at one of the speakers, begins to walk along a line perpendicular to the line joining the speakers. (Assume the speed of sound is 345 m/s.)