参量阵扬声器在管道噪声控制中的研究*

为了解决管道有源噪声控制中声反馈造成的系统复杂度和计算量的增加，文中引入参量阵扬声器作为次级声源，利用其强指向性减小控制系统的声反馈。为了验证该方法可行性，本文分别在直管和L管中，对600 Hz单频噪声和频率范围为500 Hz~1000 Hz的窄带噪声进行了管道有源噪声控制，同时测量了参量阵扬声器的管内声场和降噪范围。结果表明，参量阵扬声器声反馈小，在没有声反馈补偿的条件下对单频噪声的降噪效果基本达到了声反馈补偿条件下普通扬声器的降噪效果，对窄带噪声的降噪效果稍差。此外，通过测量管道声场和降噪量，确定了参量阵扬声器的降噪区域为误差传感器下游整个管道，降噪面积为管道整个截面。这说明参量阵扬声器作为次级声源降低了系统的复杂度和算法的计算量，并取得了较好的降噪效果。

An investigation of parametric array loudspeakers in active noise control of a duct

In order to solve the problem that the acoustic feedback cause the raise of the complexity of the system and computation of algorithms in active noise control (ANC) of ducts, the parametric array loudspeakers are introduced as the secondary source in this paper. The high directivity sound beam helps parametric array loudspeakers reduce the acoustic feedback. In order to verify the method, experiments of parametric array loudspeakers in ANC of straight and L-type ducts have been completed for 600 Hz single-tone noise and 500 Hz-1000 Hz narrow-band noise. The experimental results show that the parametric array speakers have a smaller acoustic feedback. Without feedback compensation, the noise reduction of single-tone noise is equal with loudspeakers, whereas the attenuation amount of the narrow-band noise is somewhat less. Furthermore, through measuring sound field of the duct and noise attenuation, the reduction regions are the entire downstream from error microphone, and the reduction areas are the entire transverse sections of the duct. The experiments demonstrate that the noise reduction effectiveness is well and the complexity of the system and computation of algorithms are reduced, when the parametric array loudspeakers are used as secondary source.