Application of an improved spherical omnidirectional loudspeaker array model in environmental noise pollution control.

Controlling environmental noise pollution presents a significant challenge for current noise control efforts, mainly when the noise reduction target is mobile. Traditional systems are often inadequate due to their fixed and limited coverage range, which struggles to meet the demands of a dynamic environment. In response, the paper proposes an innovative method for spatial target tracking and noise control based on spherical omnidirectional loudspeaker arrays. The process begins by constructing a precise model of the spherical omnidirectional loudspeaker array that accurately reflects the spatial coverage characteristics of sound wave propagation. Then, the three-dimensional spatial model is simplified to establish a spatial latitude and longitude mapping model, enabling real-time perception and visual management of target positions. Subsequently, according to the target position, the center node of the loudspeaker is adaptively selected, and an online secondary path modeling algorithm with variable power auxiliary noise is adopted to construct a quiet zone in the target area. Simultaneously, the control system reduces noise in the target area. As the target moves slowly, the noise reduction area moves along with the target, thus enabling the system to have full-space coverage for noise reduction. Experimental results indicate that during slow target movement, this control system successfully achieves dynamic tracking and visual management of the target. When the noise frequency is between 300 Hz and 700 Hz, during the target's movement, due to the delay in the system's update of the filter coefficients, the noise reduction effect of the system is approximately 7.6dB. However, when the target remains stationary, the average noise reduction within the established quiet zone reaches 17.8 dB.