Adaptive inverse filters for stereophonic sound reproduction

A general theoretical basis for the design of adaptive digital filters for the equalization of the response of multichannel sound reproduction systems is described. The formulation used was a generalization of the Atal-Shroeder cross talk canceller. The use of a least square approach to the digital filter design, combined with appropriate modeling delays, allowed the effective equalization of nonminimum phase components in the transmission path. A stochastic gradient algorithm is presented which facilitates the adoption of the digital filters to the optimal solution, providing the possibility of the design of the filters 'in situ' in a given listening space. Some experimental results appear at very low frequencies if the response of the filters are an exponential form.