An experimental study of a multi-size microperforated panel absorber

Abstract

A new type of microperforated panel absorber (MPA) is experimentally investigated that has holes of multi sizes instead of uniform size. The target of this research work is to obtain a wideband, thin, clean, durable, healthy sound absorber. The investigation is started using two different sizes of holes with the same percentage of each size of holes. The investigation is then extended to 3 and 4 different sizes of holes with various arrangements and percentages of each size of holes. The sizes of holes vary between 0.4 mm and 1 mm in diameter and the cavity depth varies between 10 mm and 30 mm. In general the results show that a multi-size MPA will take the advantages of each size of holes, i.e. combination of maximum peak and wider frequency band. These results enable one to build a wide band, relatively thin or single layer and predictably tunable sound absorber.