I need help for this problem. I tried applying the formula B=10log(I/Io) but I don't get right answer. Someone help me or give me suggestion/hint about what to do? The problem is as follows: At a rock concert, a dB meter registered 130gB when placed 2.8m in front of a loudspeaker on the stage. a) What was the power output of a speaker, assuming uniform spherical spreading of the sound and neglecting absorption of air? b) How far away would the sound level be a somewhat reasonable 90 dB?