| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 105 === With the vigorous development of technology, speakers have become an indispensable part of human society. Especially in recent decades, the quality of electro-acoustic products have become more demanding than ever along with the progression of consumer electronics products. The working principle of speakers is quite simple, but to satisfy different needs is still worthy of research.
To design high-quality speakers, the measurement of speaker characteristics is crucial. The main content of this thesis is to develop a speaker measuring system is to replace professional electro-acoustic measuring systems, aimed at reducing costs as well as providing a higher degree of freedom system to users and fellow researchers to meet their respective needs.
The measuring system consists of three parts: first, the electrical impedance of the loudspeaker, including utilizing it to test the stability of the earphone membranes as a realistic engineering problem.
The second part is on dynamic displacement of speakers’ diaphragms, calculating the displacement-voltage transfer function, which can determine the TS parameters in conjunction with the impedance curve. In addition, an analysis system is developed to analyze the transient response of electrical signals and displacement signals of speakers. This system is capable of automatically determining the number of waves for the signal to reach steady state.
Finally, a sound pressure level measuring subsystem is developed. Simulating the sound pressure level with TS parameters and the diaphragm displacement as well. Last, measuring diaphragm vibration mode with an optical measurement to check the peaks and valleys in the SPL curve.
All the experimental results of self-developing measuring system are compared with professional electro-acoustic measurement systems to determine its practicality.
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