Qi Y Y, Weinberg B
Department of Speech and Hearing Sciences, University of Arizona, Tucson 85721.
J Speech Hear Res. 1991 Dec;34(6):1250-6. doi: 10.1044/jshr.3406.1250.
The present exploratory project was undertaken (a) to determine the relative strength of low-frequency energy in the output of one widely used electronic artificial larynx (Servox) and (b) to assess the relative strength of low-frequency energy in vowels produced by users of this type of artificial larynx. We hypothesized that the outputs of electronic artificial larynges and the vowels produced by laryngectomized users of these devices would be characterized by significant deficits in low-frequency energy level. Five users of electronic larynges and 10 normal speakers (5 female and 5 male) provided the speech samples. Results of spectral analyses indicated that there was a significant deficit in low-frequency energy both in the acoustic signals generated by a Servox electronic larynx and in vowels produced by laryngectomized users of this type of electronic larynx. Based on these findings, a second order filter was designed and implemented digitally to compensate for the observed deficit in low-frequency energy. A perceptual experiment was completed to evaluate the effect of low-frequency enhancement on perceived speech quality. Ninety-eight percent (+/- 2%) of the responses of listeners indicated that low-frequency enhanced speech samples had better vocal quality or were more pleasant to listen to than the original speech samples. We conclude that consideration for enhancing low-frequency characteristics is warranted in the design of improved prosthetic devices for alaryngeal speakers.
（a）确定一种广泛使用的电子人工喉（Servox）输出中低频能量的相对强度；（b）评估此类人工喉使用者发出的元音中低频能量的相对强度。我们假设电子人工喉的输出以及喉切除使用者发出的元音在低频能量水平上会存在显著不足。五名电子喉使用者和十名正常说话者（五名女性和五名男性）提供了语音样本。频谱分析结果表明，Servox电子喉产生的声学信号以及此类电子喉的喉切除使用者发出的元音在低频能量方面均存在显著不足。基于这些发现，设计并数字实现了一个二阶滤波器，以补偿观察到的低频能量不足。完成了一项感知实验，以评估低频增强对感知语音质量的影响。听众98%（±2%）的反馈表明，低频增强后的语音样本比原始语音样本具有更好的音质或更悦耳。我们得出结论，在设计改进的无喉者假体装置时，考虑增强低频特性是有必要的。
