Measurement Of The MLS Diffusers Scattering Coefficient In Scaled Reverberation Chamber

It is widely acknowledged that acoustic scattering plays an important role in the auditoriumacoustics design.In concordance with previous research,most of these studies focus ondetermining the degree of diffusion from the visual and estimating the scattering coefficientroughly,in lack of measurements of typical diffuser scattering coefficient.Random-incidence scattering coefficient reflects the ratio of diffuse sound in theproportion of the total refleced sound.In2004,ISO17497was publiced,decribing themeasurement of random incidence scattering coefficient in reverberation charmber.Ourcountry has publiced the standard since2008,but the study on the measurement of scatteringcoefficient is still long way to go.Based on ISO17497and GB/T21228.1,the first measurement system for scatteringcoefficients was set in the reverberation chamber of State Key Laboratory of SubtropicalBuilding Science in SCUT.With the turntable rotating continuely,this system has measuredthe typical MLS diffusers’ scattering coefficient accurately,and has discussed the edge effectin the disk.In this paper,two rotated modes,rotated by step and rotated continuely, are taken in themeasurement of5MLS diffusers in real-scale reverberation chamber.The results indicate thateach method can measure the scattering coefficient accurately.After these work,the paper set up a measurement system for scattering coefficients in the1/10reduced-scale model of the reverberation chamber of State Key Laboratory ofSubtropical Building Science in SCUT,and measure two reduced-scale MLS diffusers withthe turntable rotated by step.The results reveal to be quite consistent with the results measuredin the reverberation chamber,demonstrating that the system in the1/10reduced-scalereverberation chamber can be applied to measure the scattering coefficient accurately.The results of this paper can provide experience for future study on the measurement ofscattering coefficient in our country,and lay the foundation for further development of thescattering coefficient date.