Abstract: An omni-directional dual bilaminar hydrophone particularly suitable for use in a towed array consisting of a cylindrical tubular housing whose ends are sealed by bilaminar piezoelectric ceramic/diaphragm subassemblies capable of axially deforming to produce an electric signal proportional to the intensity of the sound vibrations sensed. The density of the air-backed hydrophone may be readily predetermined by the spacing between the ceramic/diaphragm assemblies, and/or diameter of the housing. A plurality of such hydrophones internally connected in series assembled within a cylindrical flexible fluid filled support, such as a hose, may be used as a towed array wherein the separate hydrophones thereof are electrically connected in series parallel, or series-parallel, to produce a signal from sonic vibrations.