Research On The Design Method Of Microphone Array For Reverberation Sound Image Localization

The reverberation chamber not only can be used to measure the sound absorption and sound insulation performance of various materials and structures,but also can be used for electromagnetic interference and other tests.Because it can get relatively sufficient reflection and form a certain diffuse sound field or magnetic field.It plays an important role in the fields of acoustics,automobiles and their parts,large-scale electronic systems and military electronic products.However,up to now,the angular distribution of incident energy on the boundary of the reverberation chamber has not been correctly measured.To correctly measure the incidence of sound energy on the boundary of the reverberation chamber,it is necessary to design a microphone array that can measure the sound intensity of all sound images on the boundary of the reverberation chamber.At present,the focus of research on microphone arrays is mainly on positioning technology and directivity.However,the measurable duration and measurable energy of the microphone array with sufficient reflection have not been studied.Therefore,the design method of the microphone array for sound image localization is studied with the aid of the incident sound energy on the boundary of the reverberation chamber in field of architectural acoustics.The value of this subject is mainly reflected in the proposed method to design the microphone array for sound image localization based on the reflection on the boundary of the reverberation chamber.That is,the microphone array is designed with measurable duration and energy as performance indexes.It not only has a certain effect on the performance testing standards of the microphone array,but also has an important effect on the design of the reverberation chamber.The specific research work and innovations of this subject are as follows:Firstly,the design idea of the microphone array is proposed based on the sound energy incident on the boundary of the reverberation chamber.Based on the principle of optical reflection,considering the attenuation of sound energy in air propagation,a simulation program is developed for the incidence of sound energy at any object point in the investigation plane.The simulation result shows that the incident sound energy of five typical reverberation chambers is mainly concentrated in the range of 0?87°.The microphone array for measurement should be a geometric structure with a symmetrical center.Therefore,the hemispherical microphone array is selected as the basic research model.1.The simulation results are the spatial coordinates,arrival time,incident angles and reflection paths of all incident sound images at any object point.The angular distribution information of incident sound energy at this point is obtained through the relationship curve between angle and sound energy.The pulse waveform of incident sound energy at this point is obtained through the relationship curve between time and sound energy.The existing commercial simulation software cannot meet the research needs.2.The angular distribution results of incident sound energy on the boundaries of five typical reverberation chambers are obtained through simulation(the latter three models are the reduced models of the actual reverberation chambers).Secondly,a design method of the microphone array is proposed based on the measurable percentage of sound energy as the main performance parameter.The pulse waveform is constructed based on the positioning principle of the time-delay estimation method.The pulse separations of the single channel and the different channels are analyzed and counted.The measurable sound energy percentage of each channel of the microphone array is obtained.Based on the quantitative analysis of the percentage of measurable sound energy,two microphone array models are designed by increasing and decreasing the number of channels.This design method can quantitatively analyze the importance and necessity of each channel and estimate the measurable duration of the sound image of the microphone array.Thirdly,a simple experiment method for sound image localization is proposed.A simple experiment platform for sound image localization is designed and built.Through the experiments of four kinds of reflective structures in the anechoic chamber,the positioning effect of the microphone array is verified.Besides,the error analysis is carried out.Fourthly,the experimental method for the measurable energy percentage and the measurable duration of the microphone array are proposed.The measurable energy percentage and measurable duration of the designed microphone array are verified through the experiment in a small reverberation chamber.Besides,the error analysis is performed.