A New Sound Absorption Improvement Strategy under Low Frequency for a Rigid Micro-perforated Panel Absorbers

A micro-perforated panel absorbers (MPPs) is one of the most promising alternatives among the various types of the next-generation sound absorbers. However, the low frequency noise is difficult to tackle using the general MPPs. According to the high absorption performance of the combination of the membrane absorbers with MPPs and a finite flexible micro-perforated panel backed by an air cavity, the experimental study on the combination of a rigid and a finite flexible micro-perforated panel is carried out to reduce the noise in the low frequency. The results indicate that the resonance shifts to the low frequency. Meanwhile, the peak value becomes higher in the absorption curve of a conventional MPPs, which surface is attached to a finite flexible MPPs or a membrane, in comparison with the normal MPPs. These data demonstrate the great potential of the combination a rigid MPPs with a flexible MPPs in low frequency noise reduction. Keywords-micro-perforated panel; low frequency; finite flexible; membrane; sound absorption capability