A man stands at the midpoint between two speakers that are broadcasting an amplified static hiss uniformly in all directions. The speakers are 28.0 m apart and the total power of the sound coming from each speaker is 0.478 W. Find the total sound intensity the man hears when
(a) he is at his initial position halfway between the speakers, and
(b) after he has walked 5.0 m directly towards one of the speakers.