Abstract: A hearing aid has an electroacoustic transducing means involving face-to-face diaphragms that are driven in opposite directions to avoid imparting mechanical vibrations to the case and thus to reduce acoustic feedback occasioned by case vibrations. The diaphragms have maximum dimensions less than the sound pressure wavelengths produced in translating the amplified signal. Separately housed transducers with respective diaphragms and drivers arranged in a symmetrical arrangement are shown and a closed acoustical arrangement between the diaphragms and ear drum of the user is contemplated.