Psychological impressions and listening score when listening to audio signals composed of monosyllables and words, while subject to meaningless steady noise—introduction of weighted-mean spectral distance

A useful index for evaluating two psychological impressions of annoyance, speech audibility, and the listening score, when listening to audio signals composed of monosyllables and words, while subject to meaningless steady noise is discussed. More specifically, eight evaluation indices (SN, AI, SIL, WSPD, etc.) are introduced that reflect the mutual relationships between the spectrum level of the speech peaks and that of the noise. After careful consideration of the relationships between these indices and the psychological impressions/listening score, WSPD can be selected as a useful index. Next, prediction problems of the psychological impressions/listening score are considered. The predicted values of the psychological impressions/listening score are compared with experimental data. The predicted values are in good agreement with the observed results.