An electro-acoustical transducer device includes a body structure (101) and a differential microphone (102) located in an aperture of a wall of the body structure. The microphone includes a front side for receiving an acoustical signal and a rear side for receiving the acoustical signal in modified form. The differential microphone is arranged to produce an electrical output signal proportional to the difference of the acoustical signals at the front and rear sides. The body structure is arranged to form a chamber (105) shared with the rear side of the microphone. There are tubular channels (107) to the chamber so that the channels and the chamber constitute an acoustical filter for filtering the acoustical signal falling to the rear side of the microphone. With proper design of the chamber and the channels, it is possible to achieve acoustical filtering for background noise rejection.