Designer backings to improve micro perforated panel absorber Performance

Micro perforated (MPP) panel absorbers are an appealing alternative to traditional fiber and foam sound absorbers. Most are manufactured from metal or plastic and as such are flame resistant and lightweight. They are normally spaced from a wall, and that spacing determines the frequency range where the sound absorption is most effective. Low frequency absorption can be improved by increasing the spacing from the wall. By partitioning the backing cavity into channels, the cavity depth can be increased and varied. This will improve the absorption at low frequencies while providing broader band absorption. Alternatively, the use of double leaf micro perforated panels has been suggested to improve the performance at low frequencies. The particular configuration considered here is a double configuration with honeycomb partitioning sandwiched between the two MPP layers. Three-channel and double leaf configurations are employed inside of a small enclosure and their performance is compared to a single leaf. The results demonstrate that both configurations significantly increase the attenuation at most frequencies.