基于模态控制法的平板扬声器指向性控制算法研究

Research on directivity control algorithm of flat-panel loudspeakers based on modal control method

平板扬声器使用激励器驱动薄板产生弯曲振动从而辐射声波,已在手机、电视机等设备中得到应用.模态控制法在平板扬声器的振动控制领域已有较为深入的研究,但尚未发现将其应用于平板扬声器指向性控制的研究先例.结合屏幕发声技术与空间声重放理论,创新性引入模态控制法实现平板扬声器指向性声场控制,首次推导出从动圈式激励器驱动电压到平板扬声器模态激励的频域传递函数公式.结合数值仿真,采用模态控制法对平板扬声器声辐射特性进行指向性控制.结果表明,使用模态控制法控制波束主瓣轴向和覆盖角的效果显著,指向性控制是实现定向发声的关键.

Flat-panel loudspeakers,which use an exciter to drive a thin plate to produce bending vibration and radiate sound waves,have been used in mobile phones,TV sets and other devices.The modal control method has been studied deeply in the field of vibration control of flat-panel loudspeakers,but no precedents have been found to apply it to the directional control of flat-panel loudspeakers.Here,the modal control method is innovatively introduced to realize the directional sound field control of the flat-panel loudspeaker,and the frequency transfer function formula of the driven voltage of the driven coil actuator to the modal excitation of the flat-panel loudspeaker is derived for the first time.Based on numerical simulation,this paper uses modal control method to control the acoustic radiation characteristics of the lat-panel loudspeaker.The results show that the modal control method can control the beam main lobe axis direction and coverage angle effectively.Directivity control is the key to realize directional sound production.