Abstract
A multimicrophone array is presented that can be used to approximate the frequency dependent directional characteristics of an artificial head. The desired HRTFs can be realised by a set of appropriate filters. Such a setup may be referred to as a virtual artificial head. Virtual artificial heads are much more flexible than real artificial heads, since, e.g., the filters can be adjusted to match an individual set of HRTFs. However, virtual artificial heads are sensitive to small errors in the characteristics and the position of the individual microphones. In the present work, the relevance of different microphone topologies and the robustness with respect to positioning errors of the microphones is investigated. First, a method for optimizing the microphone positions based on a Golomb array topology, which originates from number-theoretic considerations, is introduced. The method successively computes a set of microphone positions with the possibility to vary the number of microphones without changing the general topology. Second, the robustness against positioning errors is improved by applying a white noise gain regularisation constraint for the computation of the filter coeficients. It is shown by numerical simulations, for a two dimensional array, that both procedures considerably improve the robustness.