Kasturi Kalyan, Loizou Philipos C, Dorman Michael, Spahr Tony
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083-0688, USA.
J Acoust Soc Am. 2002 Sep;112(3 Pt 1):1102-11. doi: 10.1121/1.1498855.
The intelligibility of speech having either a single "hole" in various bands or having two "holes" in disjoint or adjacent bands in the spectrum was assessed with normal-hearing listeners. In experiment 1, the effect of spectral "holes" on vowel and consonant recognition was evaluated using speech processed through six frequency bands, and synthesized as a sum of sine waves. Results showed a modest decrease in vowel and consonant recognition performance when a single hole was introduced in the low- and high-frequency regions of the spectrum, respectively. When two spectral holes were introduced, vowel recognition was sensitive to the location of the holes, while consonant recognition remained constant around 70% correct, even when the middle- and high-frequency speech information was missing. The data from experiment 1 were used in experiment 2 to derive frequency-importance functions based on a least-squares approach. The shapes of the frequency-importance functions were found to be different for consonants and vowels in agreement with the notion that different cues are used by listeners to identify consonants and vowels. For vowels, there was unequal weighting across the various channels, while for consonants the frequency-importance function was relatively flat, suggesting that all bands contributed equally to consonant identification.
研究人员让听力正常的受试者评估了语音清晰度，这些语音在频谱的不同频段上要么有一个“空洞”，要么在不相邻或相邻的频段上有两个“空洞”。在实验1中，使用经过六个频段处理并合成为正弦波之和的语音，评估了频谱“空洞”对元音和辅音识别的影响。结果表明，当分别在频谱的低频和高频区域引入一个空洞时，元音和辅音的识别性能略有下降。当引入两个频谱空洞时，元音识别对空洞的位置很敏感，而辅音识别即使在中频和高频语音信息缺失的情况下，正确率仍保持在70%左右。实验1的数据被用于实验2，以基于最小二乘法得出频率重要性函数。结果发现，辅音和元音的频率重要性函数形状不同，这与听众使用不同线索来识别辅音和元音的观点一致。对于元音，各个声道的权重不相等，而对于辅音，频率重要性函数相对平坦，这表明所有频段对辅音识别的贡献是相等的。
