| Automotive vehicle horn is one of the most essential components, its performance directly affects the traffic safety and noise pollution control. To efficiently and effectively detect automotive horn, a comprehensive automotive speaker testing system has been developed. As a portable and convenient system, standard anechoic chamber is designed and reduced to a small sound level testing case. As the sound level testing case directly affects the detection accuracy of the whole system, therefore, the perfect simulation and design of the sound level testing case is of great significance.In this paper, firstly, the sound level of the existing testing cases is analyzed and summarized, and the internal structure of the case and the acquisition algorithm are modified to improve testing accuracy. After that, we use the finite-element analysis software ANSYS to establish sound level box finite-element model. The internal space is set to the ideal gas, the tank shell is set to the boundary conditions, which also adds sound-absorbing material model. We assume electronic speaker as a point source to simulate the sound field distribution inside the box.Then we research the effects that could affect the sound field distribution inside the sound level of the test case, by changing the parameters of the model we do a number of comparative experiments, such as the box shape, the number of the sound-absorbing material absorption coefficient, the position of electronic speaker in the sound level box, and the sound pressure level and sounds frequency of electronic horn. We analyze their impact on sound field distribution inside the box. Sound level are preliminary given an improvement program of the test case.Finally, we make the use of some simulation results and the measured data of the existing system in the MATLAB platform to verify the conversion theory of sound level - the distance, and correct test data method for some improvements. |
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