穿孔膜与扬声器组合结构吸声性能研究

Study on Low-frequency Sound Absorption Performance of Perforated Membrane and Loudspeaker Composed Structures

针对穿孔膜结构低频吸声能力不足问题提出穿孔膜-扬声器复合吸声结构。将扬声器放置于穿孔膜结构后端组成复合吸声结构,可改善结构的低频吸声性能。利用传递矩阵方法建立复合结构吸声理论模型,通过数值计算软件对其吸声性能进行数值计算,并通过阻抗管实验对复合吸声结构的声学性能进行验证,结果显示复合吸声结构的理论和实验变化规律基本一致。扬声器在低频段引入一个吸声峰,调节扬声器的背腔深度可以扩大复合结构的吸声带宽,调节穿孔膜的背腔深度可以使吸声峰值向低频方向移动。合理地设计扬声器和穿孔膜的背腔深度,可以实现结构的高效低频吸声。

In view of the insufficient low-frequency sound absorption capacity of the perforated membrane structure,a perforated membrane-loudspeaker composite sound absorption structure is proposed.The loudspeaker is placed at the rear end of the perforated membrane sound-absorption structure to form a new composite structure,which has a good low frequency sound absorption performance.The sound absorption theoretical model of the composite structure was established by the transfer matrix method,and the sound absorption performance of the new composite sound absorption structure was calculated by numerical calculation software.The acoustic performance of the composite sound-absorbing structure was verified through impedance tube experiments.The results show that the variation rules of the theoretical and experimental results of the composite sound absorption structure are basically the same.The loudspeaker introduces a sound absorption peak in the low frequency band,which improves the low frequency sound absorption performance of the structure.Adjusting the back cavity depth of the loudspeaker can expand the sound absorption bandwidth of the composite structure,and adjusting the depth of the back cavity of the perforated membrane can move the peak of sound absorption toward the low frequency side.Reasonable design of the back cavity depth of the loudspeaker and the perforated membrane can realize the structure's low-frequency sound absorption with high-efficiency.