Process and device to reduce the resonant frequency of the cavities of the submersible transducers

The invention is directed to the class of submersible electro-acoustic transducers such as double "Tonpilz" transducers, wherein it is desirable to reduce the resonant frequency of the transducers while maintaining a given output power emitted by the transducers. The transducer according to the invention includes at least one horn solid with the end of a motor pillar, a hollow rigid box surrounding the horn and delimiting with the horn a cavity. The cavity communicates via a port with an external fluid, and has determined dimensions and external volume. The transducer further includes a passive radiator made of a material denser than the external fluid. The radiator obturates the port and hangs at a periphery of the port by an elastic material.