An acoustic signal pressure and a noise background are supposed incident upon a general array of hydrophone elements whose individual outputs are combined in a linear manner by means of amplifiers and time delays. Determination is made of the optimum spatial distribution of the hydrophone elements, and also the optimum combination of their outputs, in order to produce in the combined output a maximum value of peak signal in relation to the average noise background. The incident signal is not restricted to be a continuous wave of a single frequency.