调制气流声源和远程广播中语言可懂度的实验研究

调制气流声源已广泛地用来作为模拟强噪声的声源。本文的研究工作表明,适当展宽高频响应,它能作为重播语言的广播用声源。我们研制的声源;输出声功率2kw,1000Hz处输出功率不低于最大值4dB,用它来广播语言,在5.8km处,逐字记录短句的可懂度是56％。四个声源组合,在8.7km处是58％,10.2km处是32％;短文可懂度的主观评价,在8.7km处是基本听懂,10.2km处是比基本听懂差,比听懂一半又要强。由于逐字记录的条件较严,因此与测听人员的素质,主要是文化程度和责任心有关,实验表明具有高中文化程度的比初中的平均逐字记录短句的可懂度要高10％。实验值是在一般气象条件下,在室外自然环境中,多次测量的平均值,测听人员未经任何训练,所以,结论具有一定的实用价值。

AIR-MODULATED SOUND SOURCE AND EXPERIMENTAL INVESTIGATION OF THE SPEECH INTELLIGIBILITY IN LONG DISTANCE BROADCASTING

Air-modulated sound source has been used widely as a sound source analogous to high intensity noise. Investigations show that suitably raising the upper limit frequency of the air-modulated loudspeaker it can be used as a broadcasting sound source to reproduce speech and music. The power output of the sound source developed is 2000 W, the power output at 1000 Hz deviates less than 4 dB from the highest power output in its frequency range. The power output and sensitivity vs frequency curves and directivity patterns are given. The sentence intelligibility when recorded word by word at 5.8 km distance from single source is 56%. And for an array of four loudspeakers, the intelligibility when recorded word by word is 58% at 8.7 km from the sound source, and 32% at 10.2 km from the sound source. The subjective rating for the short passages is nearly intelligible at 8.7 km from the sound source, and less intelligible at 10.2 km from the sound source. The experimental result shows that the obtained values are dependent on the education level and the attention of the listeners. Since experimental condition is similar to practical condition （average weather, listening in the field and untrained listeners） and obtained conclusion are of some practical value.