Research on Acoustic Path Analysis of Ultra Low Frequency Broadband High Power Electromagnetic Transducer

High-power, extremely low-frequency (ELF) sound sources are crucial for marine engineering and research. Electromagnetic transducers, superior in output power, can generate high-power sound radiation more cost-effectively and compactly than piezoelectric and magneto-strictive ones. However, current electromagnetic transducers struggle to achieve high sound pressure levels (SPL) at ELF frequencies (<50 Hz) while staying compact. This paper proposes integrating a Helmholtz resonator into the transducer's acoustic path to boost ELF SPL and compactness. Finite element analysis verified this innovative structure's performance. A comprehensive finite element model of the electromagnetic transducer with this new acoustic path structure was developed. Unlike conventional duct-based acoustic paths, this design enhances SPL at single ELF points and generates wideband high SPL sound waves. Combining finite element calculations, equivalent circuit calculations, and experimental tests, this study successfully designed the innovative acoustic path structure. The resulting electromagnetic transducer achieves high-power, ELF sound radiation with a compact design, advancing the application and development of electromagnetic transducers in marine engineering.