A software‐oriented adaptive null‐processing technique for underwater acoustic arrays has been developed and applied to experimental data obtained from a 20×20 square array. This method, which involves spatial homodyning, is holographic in nature, with important similarities to both DICANNE and a recent holographic enhancement technique. The approach is described and evaluated, compared with other methods, and results obtained from its application to experimental underwater data are presented. The technique removes the side lobes from a source image as well as the main lobe in the null direction; a striking example of this in an underwater experiment is given.Subject Classification: [43]60.30; [43]35.65; [43]30.82.