Title: Diffusion and sound absorption properties of the quadratic residue diffuser structure with perforated panel 

Author: CAI Jun; BAO Fei; WANG Yachen; WANG Yanqin 

Affiliation: School of Environmental Science and Engineering, Shanghai JiaoTong University et al. 

Abstract: Acoustic structure study always is the academic research interest. Diffusion absorbing structure (Diffsorber) has good research value because it has both diffusion property and sound absorption property. Quadratic residue diffusers (QRD) structure which had good diffusion property was combined with the perforated panel which had good sound absorption property in this study. According to standard AES-4id-2001, the diffusion experiments were carried out to study QRD structure and ones composited with perforated-panels which had1 mm-thickness and perforated percentage of 3%, 5%, 8% respectively. The polar coordinate diagrams of different structure were analyzed to derive the diffusion coefficients. Results showed that the composite structure still had good diffusion performance in the frequency range from100 Hz to 800 Hz. The reflection sound energy of composite structure reduced obviously in the perforated panel resonance frequency range where there was about 2 dB reduction averagely. The study result can provide the reference for the design and development of diffsorber.