Let's compare the loudness of sound at different distances from two types of speakers: a home speaker operating at 1.00 Watts, and a concert venue speaker operating at 1000 Watts. Recall that normal room conversation is in the 60-80 dB range, while long-term damage to hearing can occur with chronic exposure in the 90-110 dB range. Sound greater than 120 dB exceeds the average threshold for pain, while even brief exposures to 140 dB sound can cause permanent hearing loss.

A small home speaker produces 0.200 W of acoustical power. (This is achieved, for example, by a 10-watt speaker operating at 2% electrical efficiency). If the speaker projects sound uniformly in all directions, what is the loudness of the sound (in dB) at a distance of 1.47 m from the speaker?