A logical difficulty for this hypothesis

If amplitude is the only attribute of a signal that both changes with distance and is available to a receiver, then clearly the receiver must interpret a high-amplitude version as having been produced closer than a low-amplitude version. If, instead, the receiver also has available other acoustic cues adenosine triphosphate (ATP) change with distance, such as signal degradation and reverberation, then the more important these other cues are 'Tiopronin' to judging distance the less important is amplitude, but to the extent that the receiver does rely on amplitude as a distance cue, lower amplitude will still suggest greater distance.