IMPACT OF RIGID WALL BACK SHAPE ON THE SOUND ABSORPTION PERFORMANCE OF MICROPERFORATED PANELS

Microperforated panels (MPPs) are promising sound absorbers with significant potential for enhanced performance. Numerous studies have explored ways to improve MPPs by adjusting parameters such as perforation ratio, perforation diameter, panel thickness, air gap thickness, and material choice. Typically, MPPs are installed in front of rigid, flat surfaces; however, the effect of wall shape has been largely unexplored. This study investigates the impact of three different wall shapes—flat, stair-shaped, and concave—on MPP sound absorption. Both MPPs and models of the three wall shapes were 3D-printed, and their sound absorption was evaluated using an impedance tube. The results show that stair-shaped and concave walls provide superior sound absorption, particularly in the low-frequency range, compared to flat walls with the same air gap distance. These findings suggest that non-flat wall designs, such as stair-shaped and concave, can enhance sound absorption at lower frequencies. This study highlights the potential for MPPs to be effectively installed in front of rigid walls or surfaces of various shapes, expanding their applicability across a wide range of acoustic environments.