Characterizing acoustic materials under realistic incidence conditions: building an experimental database

The characterization of acoustic materials under realistic conditions is essential for assessing their performance in practical applications. Free-field and in-situ measurement techniques provide valuable insights into the scattering and absorption properties of materials, particularly under varying angles of incidence. This study presents the development of an experimental database of impulse responses obtained using spatially-resolved measurement techniques. A 3D scanner is employed to position a measurement microphone within predefined array geometries, enabling high-resolution spatio-temporal analysis of the scattered sound field. The measurement scenarios, data structuring, and post-processing strategies are described in detail. Initial results are presented and compared using different characterization approaches, including the classical two-microphone method, plane-wave expansion, and discrete complex image-source methods. This database aims to support the development of advanced inverse methods for analyzing the complex scattering behavior of absorbers and diffusers in practical settings.