Online secondary path modeling for active sound quality control systems

The algorithms for online secondary path modeling, with the injection of auxiliary noise, have always been applied to active noise control (ANC) systems to deal with the problem of when the secondary path is time-varying. The applications of ANC in vehicles for active sound quality control may pose new challenges for the current online secondary path modeling algorithms due to the disturbance noise signal from unconcerned frequencies. Therefore, this paper presents a framework of online secondary path modeling for active sound quality control systems. On the basis of current algorithms, an adaptive step size least mean square (ASS-LMS) algorithm of the secondary path modeling with interference signals is proposed. The ASS-LMS algorithm improves the stability of iteration without reducing convergence speed. Furthermore, a modified strategy for scheduling the auxiliary noise power is also proposed. The proposed modification reduces the degradation of the sound quality control performance caused by auxiliary noise. Simulations results are provided to verify the effectiveness of the algorithms proposed in this paper.