Structural Diffuse Field Excitation Synthesis by Synthetic Array (SFS-SA), Application to Cars Panels Contributions

Diffuse field or turbulent boundary layer excitations of vehicles are of huge interest in automotive industry. For such excitations reverberation chambers or wind tunnels are necessary, this means high cost experiments. The idea of sound field synthesis to create the acoustic effect corresponding to diffuse field or turbulent boundary layer excitation, is of major interest to reduce drastically the cost of experiments. Originally, techniques based on loudspeakers antenna were used, however, a major difficulty appeared due to driving simultaneously a huge number of sources. To avoid this difficulty a new technique based on synthetic antenna is used here; instead of an array of loudspeakers, just one source is used for scanning the surface where the acoustic field excite the structure. A post processing step, based on plane wave decomposition, is then applied to collected experimental data in order to get the response of the structure or the sound transmission through the structure. Validation of the method is presented by comparing synthetic antenna results to standard measurements of panels sound transmission between two reverberation chambers. The present paper is focusing on panels contributions in a car, leading to an experimental process avoiding the cumbersome masking technique generally used in automotive industry.