Abstract: To solve the problems of the traditional Janus-Helmholtz(JH) transducer involving the indeterminacy of large response fluctuation and multiple-mode-coupling principle,the acoustic radiation performance of main independent vibration modes for the JH transducer are modeled separately and analyzed in detail by using the finite element method.It was found that weak radiation coupling occur between acoustic radiation models of JH transducer.The physical interpretation about the bandwidth characteristics could be given as follows by the results.Because no effective interference and enhancement could be used between the modes of a JH transducer with the same longitudinal driver,it would be quite difficult to obtain the broadband performance as usual.The optimization study of the electroacoustic performance is done to make its working bandwidth as broad as possible and the structural parameters is determined.At last a prototype is manufactured and measured.It is verified that the projector has good pe rformance by both the simulated and e xperimental re sults.The difference of TVR is about 12 dB in the frequency range from 1200 Hz to3300 Hz and the maximum source level is 204 dB.