AN EXPERIMENTAL STUDY ON THE SOUND ABSORPTION OF THREE-DIMENSIONAL MPP SPACE SOUND ABSORBERS: RECTANGULAR MPP SPACE SOUND ABSORBER (RMSA)

摘要

A microperforated panel (MPP) is usually placed with a rigid-back wall to form a Helmholtz resonator with its hole and the air-back cavity. However, the authors have so far proposed an MPP space sound absorber without any backing structure. In the previous studies, as a basic form of such an MPP space absorber, multiple-leaf MPP structures without a back wall were proposed, and were theoretically and experimentally examined. In order to provide more unrestricted usage and designs for an MPP space absorber, the authors have also proposed a three-dimensional MPP space absorber, called a cylindrical MPP space absorber (CMSA). The CMSA was shown to exhibit resonance peak absorption and additional low frequency absorption. In this paper, another alternative of a three-dimensional MPP space absorber, a rectangular MPP space absorber (RMSA) is proposed. Its sound absorption performance is discussed using experimentally measured results. The results show sound absorption characteristics similar to a CMSA, and an RMSA can be effectively used if properly designed.