Abstract: The Janus-Helmholtz transducer with the resonance frequency near 500Hz is presented in this paper. Firstly the theory of equivalent circuit is used for qualitative analysis of low frequency performance and ATILA finite element simulation technique is used for quantitative analysis of the transducer. Then the assembly of Janus500 is described and the Janus-Helmholtz transducer sample is developed and its performance is tested and discussed. The results indicate that the simulation analysis is relatively accurate and the coherence between double ends' vibrations is good enough. Finally the performance of the transducer in low frequency and high power is achieved.