Difference Limen for the Intensity of a Vowel Sound
James L. Flanagan · The Journal of the Acoustical Society of America · 1955
An exploratory experiment to determine just discriminable differences in the intensity of a synthetic vowel sound is described. Results of AB listening tests performed with intra-sample time spacings of 0.5, 1.0, and 1.5 seconds are given. The median value of the DL for vowel intensity obtained from the tests is 1.5 db, and the DL is never less than 1.2 db. Tentative data on the time error for a vowel sound are noted and compared to similar data for pure tones.