The growing demand for automatic surveillance systems that integrates different types of sensors, including microphones, requires to adapt and optimize the already studied techniques of Acoustic Source Localization to meet the constraints imposed by the new application scenario. In this paper, we present a real-time prototype for multiple acoustic sources localization in a far-filed and free-field environment. The prototype is composed by two linear arrays and utilizes an innovative approach for the localization of multiple sources. The algorithm is based on two steps: i) the separation of the sources by means of beamforming techniques and ii) the comparison of the power spectrum by means of a spectral distance measure. The prototype was successfully tested in a real environment.