Interactive factors in consonant confusion patterns

Confusion patterns among English consonants were examined using log-linear modeling techniques to assess the influence of low-pass filtering, shaped noise, presentation level, and consonant position. Ten normal-hearing listeners were presented consonant-vowel (CV) and vowel-consonant (VC) syllables containing the vowel /a/. Stimuli were presented in quiet and in noise, and were either filtered or broadband. The noise was shaped such that the effective signal level in each 1/3 octave band was equivalent in quiet and noise listening conditions. Three presentation levels were analyzed corresponding to the overall rms level of the combined speech stimuli. Error patterns were affected significantly by presentation level, filtering, and consonant position as a complex interaction. The effect of filtering was dependent on presentation level and consonant position. The effects stemming from the noise were less pronounced. Specific confusions responsible for these effects were isolated, and an acoustical interaction is suggested, stressing the spectral characteristics of the signals and their modification by presentation level and filtering.