Dependence of the direct sound energy upon the distance to the sound source

Abstract

It has been establised by investigations that the duration of direct sound is little dependent upon the distance to the sound source. It decreases from 0.4 ms near the source to 0.25 ms at the distance of 41 m from the source. The amplitude of direct sound decreases along with the increase in the distance to the sound source; the decrease is more marked within 11 m. [...].