Research on physical measure and subjective evaluation method corresponding to speech transmission performance of rooms.

从理论检验和主观实验两个方面阐明了STI的缺陷。对STI变化趋势的模型计算表明，STI是由时间轴上能量的集中程度决定的，这与人们普遍接受的早期能量对语音清晰度的重要性的概念相矛盾。在不同能量集中点的合成声场中进行了单词可懂度测试，结果表明存在STI与可懂度矛盾的情况。对背景噪声条件下的单次反射声场进行了可懂度测试，结果表明，尽管STI值相同，但单次反射的正、负相对水平的可懂度得分值不同，利用实际声场的脉冲响应进行了主观评价实验，并检验了与各种物理测量的对应性。结果表明，大体积空间的主观评价和每个物理测量之间的相关性显示较小的值。大体积空间语音传输性能的评价是未来的研究课题，本文研究了语音速率对可懂度的影响。在混响场中，可懂度随语速的增加而降低，而在背景噪声场中，可懂度与语速无关。混响对可懂度的降低，老年人比青年人明显，对可懂度测试方法的检验结果表明，在混响场中加入载波短语和使用快速语音速率可有效提高可懂度测试的灵敏度。结果表明，使用低熟悉度的词语可能会提高混响场和背景噪声场的可懂度测试的灵敏度。

The defect of STI was clarified by both theoretical examination and subjective experiment. The model calculation of STI on the change tendency showed that STI was determined by the degree of concentration of the energy on time axis, that contradict the widely accepted concept of importance of early energy for speech intelligibility. The word intelligibility test was carried out in the synthesized sound field with different energy concentration point, and it was shown that there is a case in which STI contradicts the intelligibility. The intelligibility test carried out for the single reflection sound field under background noise condition showed that the intelligibility score for positive and negative relative levels of single reflection took different values despite of the same STI values.The subjective evaluation experiment was carried out using impulse response of the actual sound field, and the correspondence with various physical measures was examined. It was shown that the correlation between the subjective evaluation and each physical measure showed smaller value for large volume space. The evaluation of the speech transmission performance of the large volume space is future problem.The effect of the speech rate on the intelligibility was examined. The intelligibility lowered with the increase of the speech rate in the reverberant fields, though the intelligibility is unrelated to the speech rate in background noise field. The lowering of the intelligibility by reverberation appeared clearly for elderly people than for young people.The result of the examination on the intelligibility test method showed that it was effective to raise the sensitivity of the intelligibility test to add the carrier phrase and to use the fast speech rate in the reverberant field. It was shown that the use of low familiarity words might raise the sensitivity on the intelligibility test for both reverberant field and background noise field.