Abstract: An electro-acoustic transducer is formed of a loudspeaker enclosure having a form of revolution about an axis each end of which is closed by a loudspeaker. The two loudspeakers are mounted back to back in the axis of the enclosure, one of the loudspeakers being fed from an electric power source and being in this sense "active", whereas the other loudspeaker is "passive" in that it receives no electric supply, its movements resulting from the rear wave of the active loudspeaker. The enclosure is maintained vertically along its axis of revolution, and, on the other hand, the side wall of the enclosure is formed of a flexible material, unlikely to resonate with the front and rear waves of the loudspeakers.