Irregular microphone array design for broadband beamforming

•An adaptive broadband beamforming for a sparse microphone array is proposed.•Using simulated annealing algorithm to find an irregular microphone array that maximizes the number of distinct distances between sensors in array subject to a distribution constraint. This irregular microphone is well-posed for sparse recovery algorithms.•Verifying different sparse recovery algorithms with the irregular array to determine the most suitable algorithm.•We propose an interpolation method for a dense array from sparse reconstructed sound fields. Sparse microphone array design is receiving a great deal of attention, largely due to the capacity to reduce the number of microphones. However, in general, using a sparse array for broadband beamforming still requires a large number of microphones for a complex/higher-order beam pattern, while a sparse array deployment is normally designed for a specific beam pattern. This paper aims to design a versatile sparse microphone array that can be used for different beam patterns. Furthermore, we aim to reduce the number of microphones in the sparse array while ensuring that its performance can continue to compete with a highly dense and uniform array in terms of broadband beamforming. An irregular microphone array in a planar surface with the maximum number of different distances between the microphones is proposed. It is demonstrated that the irregular microphone array is well-suited to the sparse recovery algorithms that are used to reconstruct the sound sources. From the reconstructed sound sources, an array interpolation method is presented to obtain an interpolated dense and uniform microphone array that performs well with broadband beamforming. This manuscript covers the theoretical background of the method as well as the experimental results.