In order to utilize the clearness methods for beamforming acoustic source identification exactly, imaging diagrams of the given single source, incoherent sources and coherent sources, together with corresponding performance curves were simulated and the loudspeaker sound source identification experiments were conducted. The characteristics of DAMAS2, FFT-NNLS, CLEAN and CLEAN-SC were demonstrated and compared with each other. Three conclusions were drawn. Firstly, for single source or incoherent sources, all these four methods could not only suppress sidelobes effectively but also improve resolution remarkably and CLEAN-SC has the highest accuracy rating especially. Secondly, DAMAS2 and FFT-NNLS have high accuracy rating for coherent sources, while CLEAN-SC couldn’t identify coherent sources. Thirdly, DAMAS2 has the highest computational efficiency, FFT-NNLS follows, CLEAN and CLEAN-SC are slightly slow. These conclusions have guiding significance on the exact application of these methods in practical engineering.