Direct Comparisons of the Autophonic Scale and the Loudness Scale
L. E. McMahon, James Taylor · The Journal of the Acoustical Society of America · 1963
It has been shown that a speaker's estimate of his own vocal effort grows more rapidly as a function of the sound-pressure level of his voice than does a listener's estimate of the loudness of the speech. In order to test this effect directly, the loudness of speech was judged simultaneously by a speaker and by one or more listeners. The speaker pronounced single words at different intensities; both he and the listeners estimated the loudness of the speech. Each observer served as both listener and speaker. The speaker's estimates of his loudness were plotted against the listeners' estimates. In log-log coordinates, the points approximated a straight line whose slope provided an estimate of the ratio between the exponents of the power functions relating loudness and autophonic level to SPL. The results show that the listeners' estimates grow approximately as the 0.8 power of the speaker's estimates. An exponent less than unity is a necessary condition for a stable system when two speakers try to match the loudness of their voices.