Active sound profiling system based on local secondary path

Active noise control technology has been widely applied in vehicle interior noise control. However, as traditional noise reduction methods fail to meet the increasingly prominent demand for sound quality control, active sound profiling technology emerges as a solution. Building upon traditional active sound profiling systems, a local secondary path based active sound profiling (LASP) system with multiple channels is proposed. This system employs locally identified secondary path models, obtained through an improved modeling method, to replace the global secondary path model when calculating the filtered reference signal and pseudo-error signal. This approach reduces the computational load by 94.94%, enhancing system efficiency and lowering hardware costs. Simulation analysis of the multi-channel LASP system is conducted using a combination of cancellation, attenuation, and enhancement modes, with different target sound pressure level increments set for the second, fourth, and sixth noise frequencies. The results indicate that the system control errors are all within 0.74 dB. A simulated bench test is conducted on signals collected from a certain gasoline vehicle model, and the sound profiling errors under steady-state conditions are less than 1.15 dB, with an average error under acceleration conditions within 2.58 dB. Real-vehicle tests on a hybrid multi-purpose vehicle further demonstrate that the sound profiling control errors are less than 2.20 dB. These results fully confirm that the proposed multi-channel LASP system can effectively be used for spectrum shaping and amplitude correction of multi-harmonic order noise in automobiles.