Random incidence absorption characteristics of micro-perforated panel absorbers with parallel-arranged backing cavities at different depths

To broaden the sound absorption bandwidth of micro-perforated panel absorbers under diffuse field conditions, a micro-perforated panel absorber with parallel-arranged backing cavities at different depths was designed and investigated for its random incidence absorption characteristics. An analytical model and a finite element simulation model for this absorber were established. This analytical model was used to investigate the influence of main structural parameters on acoustic performance, including the sequence of cavity depths, perforation diameter, panel thickness, and perforation rate. Full-scale absorber samples were fabricated and tested in a reverberation chamber. Results show that this analytical model is in good agreement with the finite element model and experimental measurements. It accurately predicts the absorption characteristics of this absorber in the frequency band of 500−4000 Hz, which is the primary concern in the field of architectural acoustics. After optimizing the structural parameters, the average random incidence absorption coefficient of this absorber reached 0.8 in the frequency band 490−4000 Hz.