| Summary: | 碩士 === 國立成功大學 === 系統及船舶機電工程學系 === 102 === In this thesis, a system for focusing sound around desire locations by using speakers array of controlled sources is proposed. To increase acoustic signals in certain locations where the user is within but to reduce it in the other certain locations by controlling source signals is the main objective of this study. The program based on adaptive time-reversal theory is designed to obtain input weighting coefficients for speakers using Matlab. Experiments with speakers array of controlled sources and simulations under Matlab are established in order to observe the distribution of sound field under different boundary and control conditions.
To test this system, a variety of simulation conditions are used, such as: the number of speakers array sources, the number of receivers, and emission source frequency. As for experiment, in the free field and reflected sound field under LabView are taken to compare results. Based on simulations and experiments, effects of controlled sound field are obtained. Finally, from general sound field experiments, the difference of sound pressure level between bright point and dark point is 5 ~ 12dB. Therefore, general sound field energy focusing is realized via present algorithm and expected to have a diversification of use in the future.
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