The realization of non-directional linear electroacoustic arrays using Bessel weighting has been described in the literature. In this paper, we discuss generalized allpass arrays; since the far-field response of a uniformly spaced linear array is specified by a mapping of the DTFT of the array weights, any FIR approximation of an allpass filter gives weights which result in a nearly uniform array response as achieved by Bessel arrays. We explain the fundamental array theory and present a straightforward method for the design of arbitrary-order allpass arrays. We then discuss applications of allpass arrays in crossover-filtered configurations and in the implementation of efficient frequency-invariant beamformers.
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