One of the reason for which the split type air-conditioner (AC) is preferred over window mounted air-conditioner is low noise. However, the outdoor unit of split type AC produces significant noise predominantly in low frequency regime and typically below 200 Hz. The sonic crystal, which is found suitable for outdoor noise control, is endeavored for attenuating the noise of outdoor unit of split type ACs. The challenge of designing a finite sonic crystal with scatterers having low diameter and minimum number of rows to attenuate the low frequency noise is addressed in present research by suggesting a tuneable multi resonant scatterer. The scatterer is made with multiple hollow compartments in the direction of height and having perforations which is tuned using finite element analyses. At last, the sonic crystal is fabricated and acoustically characterized in an anechoic chamber. The experimental investigations are conducted by deploying the sonic crystal near outdoor unit of three split type ACs and the noise measurements exhibit that the overall noise levels reduce by ≈7 dB.

与窗户安装式空调相比，首选分体式空调（AC）的原因之一是低噪音。但是，分体式AC的室外机主要在低频状态下且通常低于200 Hz时会产生明显的噪声。已发现适合于控制室外噪声的声波晶体，其目的是衰减分离式AC室外单元的噪声。在本研究中，通过提出一种可调谐的多共振散射体，解决了设计具有有限直径的声波晶体的挑战，该晶体具有直径较小且行数最少的散射体以衰减低频噪声。散射体在高度方向上具有多个中空隔室，并具有穿孔，可使用有限元分析对其进行调整。终于，在无回声室中制造声晶体并对其进行声学表征。通过在三个分体式AC的室外机附近部署声晶体来进行实验研究，并且噪声测量结果表明，总体噪声水平降低了≈7dB。