Micro-Perforated Panel

A micro-perforated panel (MPP) is a thin sheet with sub-millimetre holes (typically 0.1–1.0 mm diameter) that provides sound absorption without requiring a fibrous backing material. Developed by Maa Dah-You in the 1970s, MPPs achieve absorption through viscous losses in the micro-perforations themselves. The panel is mounted over an air cavity, and the system is tuned by adjusting hole diameter, perforation ratio, panel thickness, and cavity depth. MPPs are valued in clean environments (food processing, swimming pools, museums) where fibre-shedding materials are unacceptable. Clear acrylic and glass MPPs provide simultaneous sound absorption and transparency. Single-layer MPPs have relatively narrow absorption bandwidth, but double-layer and partitioned-cavity designs extend the effective range. Research into MPPs is active, with 3D-printing enabling complex geometries for broadband absorption.