Robustness of 3D Sound Systems

Abstract

The solution for the control filters in the generalised audio reproduction model discussed in Section 3.1 consists of two elements. The first is the cross-talk canceller, which is the inverse of the matrix of electro-acoustic transfer functions between the reproduction loudspeakers and the listeners’ ears. The second is the matrix of electro-acoustic transfer functions representing the desired response. Since both elements are dependent on space coordinates, the solution for the control filters is inherently dependent on space coordinates, independent of the method used to calculate the filters. A set of filters designed to give optimum results at a specific listening situation is, in general, in error when a listener moves. In this chapter, the nature of those errors is discussed and methods to improve the system robustness against listeners’ movements are introduced. The problem is divided into two subproblems: the first deals with enlarging the zones of equalisation created around the control microphones and the second tracks the listeners when they move beyond those equalisation zones.