It has been assumed that similar sounds should appear alike to all ears with equal acuity of hearing as determined by the standard tests, that the loudness of a sound always corresponds to the number of decibels above minimum audibility and that the sensation of loudness may be predicated with confidence on the usual functional tests for hearing. I shall demonstrate the fallacy of all these assumptions.
In the past all methods for measuring acuity of hearing have been based on the ability of the ear to detect the faintest audible intensity. In every case it has been taken for granted that if the hearing is deficient for faint sounds it is also in like proportion deficient for louder sounds. In other words, if the hearing is down, say 30 units, at any or all intensities, it will require 30 extra units at any or all intensities to make it