Investigation on low frequency acoustic characteristics of parallel-arranged microperforated panel with aerogel-filled back cavities

Parallel-arranged microperforated panel (PMPP) absorber has an improved sound absorption performance compared with the single microperforated panel (MPP) absorber. However, its low frequency sound absorption depends on the use of some bulky structures. Therefore, we present a PMPP absorber that can achieve above 80% continuous sound absorption within 430–800 Hz with a thickness of only 3.3 cm. The PMPP absorber is composed of five different MPP members, each of which contains a perforated panel and a back cavity partially filled with different aerogel (AG). The resonance frequency of each MPP member shifts to lower frequencies because of the increased effective cavity depths, which can be adjusted by changing the acoustic impedance of the AG. The analytical model of the PMPP absorber is also proposed, and good agreement is observed between the predicted results and the experimental results. This finding and proposed method may provide new design guidance for the practical application of the PMPP absorber.