Abstract:The electromagnetic sound source with membrane structure has the advantages of large volume displacement, controllable ultra-low frequency sound field and good adaptability, so it has broad application prospect in the field of minesweeping sound source. Radiation film is the core vibration component of sound source. It is of great significance to study the vibration characteristics of radiation film for the design and application of electromagnetic sound source. In this paper, an analytical method for the vibration characteristics of an electromagnetic sound source with membrane structure is studied. Firstly, the analytical model of the free vibration of the ring film of the electromagnetic sound source in vacuum is established. Secondly, the natural frequency and mode of the free vibration of the ring film in vacuum are obtained by using the method of separation of variables. Then, the influence of different boundary conditions and the change of the radius of the ring membrane on the vibration characteristics of the membrane in vacuum is analyzed. Finally, considering the influence of viscous liquid load and internal filling pressure, the amplitude-frequency characteristics and volume-displacement of the low frequency forced vibration of the ring film with different sizes in the actual working conditions of the electromagnetic sound source are obtained. The method presented in this paper can accurately reflect the vibration characteristics and sound radiation capacity of the electromagnetic sound source under actual working conditions, and can provide an important reference for the design and structural optimization of high-power electromagnetic sound source.