Improving the Sound Absorption Characteristics of Micro-Perforated Panel Absorber through Multi-Cavities Arrangement

The micro-perforated panel (MPP) absorber has provided better noise control solutions in the medium to high-frequency range than the traditional fibrous porous absorbers regarding absorption characteristics and durable features in challenging environments. But, the low-frequency performance of the MPP absorber with a constrained air back cavity is not satisfactory. Researchers in the last decades proposed many solutions to enhance the acoustic performance of the absorbers, but the cost and complexities involved limited their wide applications. In this paper, the back cavity is partitioned to have a multi-cavities arrangement behind the MPP, which facilitates the multiple Helmholtz resonator (HR) effects. Maa model for the MPP absorber is modified to accommodate multiple HR effects and find the acoustic impedance and sound absorption coefficient of the proposed absorber. The individual absorption peaks of the absorber can be tuned along the frequency axis to have wideband absorption characteristics. 3D printed MPP sample with a multi-cavities structure is mounted in two microphone impedance tube setup to validate the predicted results.