中文摘要：

基于小型混响室法测量某汽车前围板内隔音垫的吸声系数，探究被测试件、声源及传声器布置形式对测量结果的影响规律，结果表明：三者均对低频结果有较大影响，对中高频结果的影响很小。要准确获得吸声系数，应采取尽可能多的配置并对所有结果取平均；该隔音垫的平均吸声系数约为0．45。进一步基于混响室一消声室声强法测量其插入损失，识别其隔声薄弱部位，结果表明：该隔音垫的平均插入损失约为12dB，转向机构、空调鼓风机及转向机防尘罩安装位置为隔声薄弱部位。研究结果为该隔音垫声学性能的分析改进提供了依据，也为声学材料性能研究试验的实施提供了参考。

英文摘要：

The sound absorption coefficient of the inner soundproof pad of a certain automobile dash panel is measured by using the reverberation room method, and the influence rules of test-piece arrangement, acoustic source position and microphone layout on measurement results are probed into. Results show that all the three factors generate obvious influences on the results at low frequencies, whereas almost no influences on the results at medium-high frequencies. Consequently, in order to obtain the sound absorption coefficient accurately, it is necessary to consider as many con- figurations as possible and average the results of all the configurations. The average sound absorption coefficient of the inner soundproof pad is about 0.45. Further, its insertion loss is measured and its primary acoustic weak links are identified based on the reverberation-room and anechoicroom method with sound intensity testing. Results show that the average insertion loss of the inner soundproof pad is about 12 dB, and the primary sound isolation weak links are the mounting positions of the steering mechanism, the A/C blower and the steering gear＇s dust cover. This study will provide not only a basis for the analysis and improvement of this inner soundproof pad＇s acoustic properties but also guidance for the acoustical materials＇ property test.