At a recent rock concert, a dB meter registered 114 dB when placed 1.30 m in front of a loudspeaker on the stage.
(a) What was the power output of the speaker, assuming a hemispherical radiation of the sound and neglecting absorption in the air?
(in units of W)
(b) How far away would the intensity level be a somewhat reasonable 85 dB?
(in units of m)