An Evaluation of a Spoken Language Interface

Abstract

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Callsign Acquisition Test (CAT): Speech Intelligibility in Noise

“…Comparing data for all cases, results obtained under SNR Ϫ9 and pink noise had the largest (Ϯ21), whereas multitalker babble with SNR -6 had the smallest (Ϯ7) standard deviations. A repeated-measures, two-factor ANOVA of speech recognition scores for SNR (three levels) and type of noise (NOISE, three levels) showed significant effects of both main factors; SNR [F (2,16) A review of Figure 4 shows that listeners had the least difficulty hearing CAT items when white noise was used. The multitalker babble makes it a little harder to hear the test items than the white noise, and pink noise was the most effective speech masker of all the three.…”

“…The standard deviations for the mean scores varied from Ϯ5 (86 dB, SNR ϭ Ϫ6) to Ϯ21 (74 dB, SNR ϭ Ϫ12). The ANOVA results showed significant effects of SNR [F (2,18) ϭ 252.52, p Ͻ 0.05] on the speech intelligibility of the CAT items. The overall level of pink noise [F(2,18) ϭ 4.22, p ϭ 0.031] was also significant, whereas the interaction between SNR and level of noise [F(4,36) ϭ 0.69, p ϭ 0.32] was not significant.…”

“…This analysis revealed no significant effect of noise level when the difference in levels was 6 dB (between 74 and 80 dB and 80 and 86 dB) but was significant when the difference was 12 dB (between 74 and 86 dB). The ANOVA results for speech intelligibility rating indicated that SNR [F (2,14) ϭ 103.90, p Ͻ 0.05] was the only significant factor, whereas pink noise level and the interaction term between SNR and pink noise level were not significant. Additionally, a one-way ANOVA of data averaged across all tests in experiment B revealed that the mean scores of speech intelligibility and intelligibility ratings were not significantly different [F(1,7) ϭ 0.32, p ϭ 0.25].…”