Comparison of sound absorption performance of aluminium and cardboard micro-perforated panel

Blurry noise or echo can cause disturbance to human being, especially in big halls, classrooms, auditoriums, cinemas and offices. This paper discusses the application of aluminium and cardboard micro-perforated panels (MPP) as acoustic absorber. Samples of MPP with different materials and perforation ratios are fabricated. The effect of type of material, introduction of air gap behind the sample and perforation ratio on the sound absorption performance are investigated through impedance tube testing to obtain the sound absorption coefficient. Both the aluminium and cardboard MPP are found to be effective acoustic absorber, especially at lower frequencies.