Two loudspeaker, 4.0 m apart and facing each other, play identical sounds of the same frequency. You stand halfway between them, where there is a max. of sound intensity. moving from this point toward one of the speakers, you encounter a min. of sound intensity when you move 0.25m. a) What is the frequency of the sound? b) If the frequency is then increased while you remain 0.25m from the center, what is the first frequency for which that location will be a maximum of sound intensity?