Magnitude-estimation scaling of computerized (digitized) speech under different listening conditions

The purpose of this study was to evaluate the quality of tape-recorded spee ch sentences and speech sentences digitized at low, moderate, and high samp ling rates by young adults under different listening conditions (quiet vs n oise) using magnitude-estimation scaling. A single group of 24 young adults participated as subjects. The tape-recorded speech sentences and digitized speech sentences were presented to each subject in quiet and in the presen ce of background noise at a signal-to-noise ratio of 0 dB. The subjects wer e instructed to use magnitude-estimation scaling co evaluate these sentence s by assigning a number that corresponded to the speech quality of each sen tence. An analysis of variance with repealed measures was performed to asse ss the effects of mode of speech and listening condition on the magnitude-e stimation responses. The analysis showed that the main effects for mode of speech and listening condition were statistically significant. The interact ions of mode of speech by listening condition were also statistically signi ficant. Pairwise comparisons showed that the magnitude-estimation responses were higher in the quiet condition than in the corresponding noise conditi on for each level of mode of speech. Based on the results, the implications of the present study and several avenues for later research are discussed.