An applicability discussion of the in-situ measurement method using the ensemble averaging technique for sound absorption characteristics

In our former papers, the authors have proposed a measurement method for sound absorption characteristics, surface impedance and sound absorption coefficient, of materials using the ensemble averaging technique. We named it EA-method, for short. So far, we have shown the robustness as well as the reproducibility of the results obtained by the method at various environments. The method consists of two kinds according to sensor types employed: i.e. two-microphone and PU-sensor. In this paper, the applicability of the EA-method is discussed onto three types of absorption: porous, panel, and resonator. At first, the outline of the EA-method is summarized and measurement mechanism is explained. Then, the robustness as well as the reproducibility of the method are discussed based on accumulated results of measurements conducted in various environments including reverberation rooms and in-situ conditions.