EVALUATING THE ARTICULATION INDEX FOR AUDITORY-VISUAL CONSONANT RECOGNITION

Adequacy of the ANSI standard for calculating the articulation index ( AI) [ANSI S3.5-1969 (R1986)] was evaluated by measuring auditory (A), visual (V), and auditory-visual (AV) consonant recognition under a var iety of bandpass-filtered speech conditions. Contrary to ANSI predicti ons, filter conditions having the same auditory AI did not necessarily result in the same auditory-visual AI. Low-frequency bands of speech tended to provide more benefit to AV consonant recognition than high-f requency bands. Analyses of the auditory error patterns produced by th e different filter conditions showed a strong negative correlation bet ween the degree of A and V redundancy and the amount of benefit obtain ed when A and V cues were combined. These data indicate that the ANSI auditory-visual AI procedure is inadequate for predicting AV consonant recognition performance under conditions of severe spectral shaping. (C) 1996 Acoustical Society of America.