1. A method comprising: (a) identifying angles of acoustic sources from peaks in an amplitude envelope, wherein the amplitude envelope corresponds to an output of a virtual broadside scan on blocks of input signal samples, one block from each microphone in an array of microphones, wherein the microphones of the array are arranged on a circle, wherein the virtual broadside scan comprises scanning a virtual broadside array through a set of angles spanning the circle in order to generate said output, wherein the virtual broadside array operates on the blocks of input signal samples; (b) for each of the source angles, operating on the input signal blocks with a directed beam pointed in the direction of the source angle to obtain a corresponding beam signal, wherein each of the beam signals has a corresponding energy; (c) classifying each of the sources as speech or noise based on analysis of spectral characteristics of the corresponding beam signal, wherein one or more of the sources are classified as speech; (d) of those one or more sources that are classified as speech, identifying one or more sources whose corresponding beam signals have highest energies; (e) generating an output signal from the one or more beam signals corresponding to the one or more speech sources having highest energies.