Abstract: 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.

Abstract: The object of the present invention is a process wherein transducers submed in a fluid for emitting low frequency acoustic waves with lightened horns are used to reduce the frequency of emission for a given maximum power consumption of the transducer. The transducer transmits waves in a frequency range according to the given maximum power consumption and a given electro-acoustic efficiency. The transducer comprises at least one horn solid with the extremity of a motor pillar and a rigid box. The rigid box encloses the motor pillar and has determined dimensions and external volume, and further includes a dynamic load solid with the rigid box. The dynamic load partially closes an inside section of the rigid box and divides an internal cavity into a front cavity and rear cavity. The front and rear cavities communicate.