“小房间”的低频混响时间特性对音质的影响

Influence of Low Frequency Reverberation Time Characteristics of Small Room on Sound Quality

从分析声学“小房间”的室内声场和语音声学特性出发,探讨“小房间”(普通教室)在低频段的声场共振现象,研究低频混响时间特性对普通教室音质的影响。增强的低频驻波声级对中高频信号具有极大的掩蔽作用,会导致教室语言清晰度降低,因此,不能忽略过长的低频混响对教室音质的负面影响。此外,实验测定并分析了音质表现极差与优异(声学改造前后的表现)的私家听音室的混响时间特性及其变化,结果表明,在低频段下降的混响时间特性是听音室获得优异音质的关键。基于此,对加装扩声系统的普通教室提出声学处理建议。

Based on the analysis of the indoor sound field and voice acoustic characteristics of“small room”,this paper discusses the sound field resonance phenomenon of“small room”(ordinary classroom)in low frequency,and studies the influence of low frequency reverberation time characteristics on the sound quality of ordinary classroom.The enhanced low-frequency standing wave sound level has a great masking effect on medium and high-frequency signals,which will lead to the reduction of classroom language clarity.Therefore,the negative impact of long low-frequency reverberation on classroom sound quality cannot be ignored.In addition,the reverberation time characteristics and their changes of private listening rooms with extremely poor and excellent sound quality(i.e.performance before and after acoustic transformation)are measured and analyzed.The results show that the decreasing reverberation time characteristics at low frequency is the key to obtain excellent sound quality.Based on this,this paper puts forward some suggestions on the acoustic treatment of the ordinary classroom with sound reinforcement system.