MULTIPLE-LEAF SOUND ABSORBERS WITH MICROPERFORATED PANELS: AN OVERVIEW

摘要

Since the pioneering work by Maa, multiple-leaf microperforated panel (MPP) sound absorbers of various configurations with different materials have been studied. Multiple-leaf structures are primarily employed to obtain wideband sound absorption. The authors have proposed double-leaf microperforated panel space absorbers (DLMPP), which consist of two MPPs and an air-cavity in-between, without a back wall. A DLMPP is a wideband sound absorber, which is also effective at low frequencies. However, an MPP is still expensive. If one of the MPPs in such a structure can be substituted by another material, such as a permeable membrane, it can be effective and also economical. The authors, therefore, have been exploring various multiple-leaf structures including both MPPs and permeable membranes. This paper gives an overview of our studies on such multiple-leaf sound absorbing structures with MPPs, including a DLMPP, a triple-leaf MPP space absorber, a space sound absorber consisting of an MPP and a permeable membrane. Also it includes a multiple-leaf structure with MPPs and membranes backed by a rigid wall.