Sensitivity Analysis of a Beamforming Technique for Acoustic Measurements

Beamforming is a technique that is used to determine the location of an acoustic source and the sound level spectrum of the signal produced by the source. This technique involves an array of microphones which record acoustic signals at multiple locations. A detailed analysis of the beamforming technique was carried out for three different array geometries: a uniform linear array, a uniform planar array, and a random array. The effect of various parameters, such as the number of microphones in an array, on the applicability of the technique was examined using both simulations and experiments. The simulation results established that the source localization capability of a uniform linear array is limited to an acoustic source lying in the plane of the array. In contrast, a planar array (either uniform or random) does not suffer the above limitation. The results also showed that a random array (eg., a spiral array) is the best of all the array geometries. The experimental results demonstrated the robustness of the beamforming technique in localizing an acoustic source and also confirmed the superiority of a uniform planar array over a uniform linear array.