紧凑型双单元声系统的波束形成研究

On the beamforming of a compact dual-speaker sound system

紧凑型扬声器系统的空间感增强是目前便携式移动电声设备面临的一个重要难题。该文基于拓宽视在声源宽度以增强空间感的理念,进行了紧凑型扬声器系统的波束形成研究。该文基于圆柱形刚性障板的声学特性,利用两只扬声器单元设计了紧凑型双单元声系统,分别利用基于相位对齐的最小均方误差算法实现左/右声道的波束形成和利用最小均方误差算法并设计半空间指向性的目标实现虚拟中央声道的波束形成。通过分析波束宽度和扬声器单元的工作状态验证了波束形成效果符合目标设计。考虑到实际使用情况,一方面,该文利用边界元方法仿真分析了有限长障板对扬声器单元指向性以及波束形成的影响,仿真结果表明有限长障板会使得单元整体的指向性变宽,该结果更有利于声系统实现目标;另一方面,该文基于有限元仿真的条件实际设计了双单元声系统,通过实验测量进一步验证了算法的性能。

Spatial impression enhancement of compact loudspeaker systems is an important problem faced by portable mobile electroacoustic equipment at present.Based on the idea of broadening the apparent source width(ASW)to enhance the spatial impression,this paper studies the beamforming of a compact loudspeaker system.Based on the acoustic characteristics of the cylindrical rigid baffle,a compact dual-speaker sound system is designed by using two loudspeakers.The left/right channel beamforming is realized by using phasealigned minimum mean squared error(MMSE)algorithm,and the phantom center channel beamforming is realized by using MMSE algorithm and designing a half-space directional target.By analyzing the beamwidth and the operating state of loudspeakers,it is verified that the beamforming effect is in accordance with the target design.Considering the actual application,this paper uses the boundary element method to simulate and analyze the influence of the finite-length baffle on the directivity of loudspeaker and beamforming.The simulation results demonstrate that the finite baffle can widen the directivity of the loudspeaker,which is more conducive to the realization of the target of the sound system.On the other hand,this paper further validates the performance of the algorithm by experimental measurements.