9. Two loudspeakers are located 3.00 m apart on the stage of an auditorium. A detector is placed 20.0 m from one speaker and 21.2 m from the other. A signal generator drives the two speakers in phase and sweeps through the range (2 KHz-20 KHz). Assume that the speed of sound in air is 343 m/s. (a) What is lowest note (frequency) for which destructive interference is a maximum? (b) What is highest note for which destructive interference is a maximum? (c) What is the lowest note for which constructive interference is a maximum? (d) What is the highest note for which constructive interference is a maximum? 3 m 21.2 m 20.0 m