Research On Acoustic Focusing Of Speaker Array Directional Source And Active Noise Control

Based on the theory of array antenna and phased array technology,this paper studies the acoustic directional propagation technology of line array and plane array loudspeakers from the basic theory,numerical simulation,experimental comparison and other aspects.The phased beam deflection technology of loudspeaker array is applied to the field of active noise control,and the active control experiment of vector sound is carried out to realize the control of vector sound field in full space.Firstly,the theory of array antenna is introduced and the characteristics of its pattern are analyzed.Then,the change rule of the radiated sound field caused by the vibration of the sound source and the interference superposition principle of the sound wave are introduced.Based on the theory of array antenna and the theory of sound field radiated by point source sound wave,the formation of directivity of linear,planar and cylindrical loudspeaker array,the influence of array element delay on beam directivity and the factors affecting array directivity are discussed respectively.Secondly,Matlab is used to simulate the effects of the input signal wavelength,the number of elements,the distance between elements and the delay of the input signal on the lobe width,sidelobe and direction of the directivity graph.Finally,a series of experiments of line array,plane array directivity and deflection are built and compared with the simulation results.The experiment and test of vector sound control based on loudspeaker array are carried out with Lab VIEW.Based on a large number of numerical simulation and experimental results,the results of this paper show that: on the one hand,by using the loudspeaker array,under certain conditions,the sound beam with strong directivity can be obtained,and by controlling the delay of array element signal,the beam can be directionally propagated in the space along the preset direction.On the other hand,the directional sound source based on the loudspeaker array is applied to the field of active noise control,which realizes the three-dimensional active control of the initial sound source in the case of oblique incidence.It can realize the active noise reduction of full space vector sound field in special environment and special application,and has great innovation in the prediction of space sound field,active control strategy,system convergence mode,etc.