Freyman R L, Nerbonne G P
Department of Communication Disorder, University of Massachusetts, Amherst, USA.
J Speech Hear Res. 1996 Dec;39(6):1124-37. doi: 10.1044/jshr.3906.1124.
The perceptual consequences of expanding the amplitude variations in speech were studied under conditions in which spectral information was obscured by signal correlated noise that had an envelope correlated with the speech envelope, but had a flat amplitude spectrum. The noise samples, created individually from 22 vowel-consonant-vowel nonsense words, were used as maskers of those words, with signal-to-noise ratios ranging from -15 to 0 dB. Amplitude expansion was by a factor of 3.0 in terms of decibels. In the first experiment, presentation level for speech peaks was 80 dB SPL. Consonant recognition performance for expanded speech by 50 listeners with normal hearing was as much as 30 percentage points poorer than for unexpanded speech and the types of errors were dramatically different, especially in the midrange of S-N ratios. In a second experiment presentation level was varied to determine whether reductions in consonant levels produced by expansion were responsible for the differences between conditions. Recognition performance for unexpanded speech at 40 dB SPL was nearly equivalent to that for expanded speech at 80 dB SPL. The error patterns obtained in these two conditions were different, suggesting that the differences between conditions in Experiment 1 were due largely to expanded amplitude envelopes rather than differences in audibility.
在频谱信息被与语音包络相关的信号相关噪声掩盖的条件下，研究了扩大语音幅度变化的感知后果，该噪声具有与语音包络相关的包络，但幅度谱平坦。从22个元音-辅音-元音无意义单词中单独创建的噪声样本被用作这些单词的掩蔽音，信噪比范围为-15至0 dB。幅度扩展在分贝方面为3.0倍。在第一个实验中，语音峰值的呈现水平为80 dB SPL。50名听力正常的听众对扩展语音的辅音识别性能比未扩展语音差多达30个百分点，并且错误类型有显著差异，尤其是在信噪比的中值范围内。在第二个实验中，改变呈现水平以确定扩展导致的辅音水平降低是否是条件之间差异的原因。40 dB SPL时未扩展语音的识别性能几乎等同于80 dB SPL时扩展语音的识别性能。在这两种条件下获得的错误模式不同，这表明实验1中条件之间的差异主要是由于幅度包络的扩展而不是可听度的差异。
