Two loud speakers are located 3.35 m apart on an outdoor stage. A listener is 18.3 m from one and 19.5 m from the other. During the sound check, a signal generator drives the two speakers in phase with the same amplitude and frequency. The transmitted frequency is swept through the audible range (20 Hz to 20 kHz).

(a) What is the lowest frequency fmin,1 that gives minimum signal (destructive interference) at the listener’s location?

(b) By what number must fmin,1 be multiplied to get the second lowest frequency fmin,2 that gives minimum signal

(c) the third lowest frequency fmin,3 that gives minimum signal?

(d) What is the lowest frequency fmax,1 that gives maximum signal (constructive interference) at the listener’s location?

(e) By what number must fmax,1 be multiplied to get the second lowest frequency fmax,2 that gives maximum signal ?

(f) the third lowest frequency fmax,3 that gives maximum signal?