Effects of array scaling and advanced beamforming algorithms on the angular resolution of microphone array systems

Several advanced beamforming methods have been developed in the past 20 years that have dramatically improved the angular resolution of microphone array systems. Meanwhile, the Rayleigh criterion has long been considered the standard criterion for angular resolution of such systems. In this investigation four microphone arrays were constructed as scaled models of a fifth microphone array. All of the arrays were subjected to a thorough regimen of testing with both broadband and narrowband sources. Using conventional beamforming, the angular resolution of each scaled array was determined as a function of frequency and compared to the Rayleigh criterion. The analysis was repeated with the advanced TIDY, DAMAS, DAMAS2, and CLEAN-SC beamforming algorithms so that the effects of array scaling and advanced beamforming can be determined as a function of frequency and compared to conventional beamforming.