Sound Field Fitting Method Of Spatial Point Sound Source Based On Multi-channel Standard Sound Source

With the continuous development of microphone array measurement technology,the positioning accuracy of microphone arrays has become more and more demanding.The accuracy of microphone array itself directly affects the final sound source identification and positioning accuracy,so the research on microphone array calibration becomes more and more important.The traditional idea of microphone array calibration is to calibrate each microphone on the microphone array(including frequency,amplitude and phase calibration).In the case of a large number of microphones,this calibration method is time-consuming and labor-intensive,and the actual usage environment(humidity,temperature,etc.)of the microphone array may change compared with the calibration environment,resulting in poor calibration results.Therefore,there is a need to study a method that can quickly calibrate microphone arrays in real-world environments.In this paper,a spatial point source simulation method is studied,a coupled cavity standard sound source with excellent performance is developed,a set of spatial simulation point source reconstruction system is built by applying multi-channel standard sound source,and the overall accuracy of microphone array is quickly calibrated by using this system to synthesize a standard spatial point source,which significantly improves the noise source identification and localization accuracy of microphone array,and the study is divided into the following aspects.(1)Using point source theory,a simulated point source spatial free field reconstruction algorithm is derived and a set of point source simulation software is developed.The method can calculate the dynamic signals collected by each microphone of the microphone array in the spatial free point source sound field,which provides theoretical support for the simulated point source sound field reconstruction system.(2)Lab VIEW is used to simulate the reconstruction process of the point source and the localization process of the microphone array to the point source.By changing the array type,the number of microphones,the microphone spacing and other elements of the microphone array,the accuracy and stability of the localization results of the microphone array to the simulated point source are observed,and it is determined that the point source reconstructed by the simulated point source reconstruction algorithm will not introduce errors to the localization of the microphone array.It is proved that the simulated point source algorithm has universal applicability(3)A coupled-cavity standard sound source is designed,and a spatially simulated point source reconstruction experiment verification system is built based on the coupled-cavity standard sound source,multi-channel data output system and point source simulation software.The point source simulation software calculates the dynamic acoustic signals that should be obtained at the microphones at a given position,and outputs these dynamic signals to each microphone via the coupled cavity standard sound source through the multi-channel data output system,thus realizing the hardware reconstruction of the simulated point source and the actual sound field output.(4)Experimental verification of microphone array positioning accuracy by using the point source reconstruction system,through analysis and linear fitting of the positioning results of the point source,the empirical curve of microphone array error is determined,thus realizing rapid calibration of microphone array positioning accuracy and replacing the traditional method of calibrating each microphone one by one.