The influence of acoustic cavity on operating characteristics of electrodynamic transducer

The influence of acoustic cavity structure on the acoustic performance of electrodynamic transducer is not considered in traditional design theory.It leads to a big difference between the theoretical design results and the measured results.In the research,the three-segment air cavity inside electrodynamic transducer is regarded as the abrupt cross-section acoustic cavity,the equivalent circuit of the acoustic cavity is added to the traditional equivalent circuit of electrodynamic transducer.Then the improved equivalent circuit of electrodynamic transducer is obtained.Based on the equivalent circuit,the source level with acoustic cavity structure is solved,and the source level with acoustic cavity structure is also simulated by ANSYS software.The results show that the two source level curves are basically the same,which verifies that the improved equivalent circuit is correct in predicting the source level of electrodynamic transducer.The effects of acoustic cavity structure size,end acoustic boundary and cavity gas acoustic parameters on the characteristics of source level are studied.The results show that laying the sound-absorbing material at the end of the acoustic cavity or filling the acoustic cavity with a gas with low characteristic impedance has a significant effect on suppressing or eliminating the fluctuation of source level.