本文主要內容為利用數值分析來模擬揚聲器在有限空間內，對於頻率的表現應用在筆記型及薄型3c產品，並在有規範ISO 3745無響室內使用LMS聲音測試儀器進行量測與數學模擬分析來加以比對。本研究需維持原有音壓大小及空間下，主要貢獻有三點，其一為揚聲器之數學分析模型， 利用T-S參數模擬單體與導音管，並對功能做實際量測及驗證；本研究貢獻之二，為在有限空間下更換揚聲器增加低頻表現，脫離傳統改變音箱大小及導音管設計；貢獻之三為揚聲器藉由本分析流程可減少設計時間及成本。實驗結果發現，原先導音管設計低頻起振點為1300Hz，而本實驗的設計低頻起振點為800Hz，低頻表現增加500Hz；原先導音管設計須在800Hz以後失真表現才低於10%，而本研究設計在400Hz之後就低於10%，可清楚的從音樂表現上聽出2個表現的差異；聲音表現Q值從原本的1.22改變為0.81越接近在人耳中的最佳表現，且在音箱設計上減少許多困難度。 文中針對有限音箱內揚聲器的變化做了一系列的分析與實測研究，同時也針對音壓（Sound press level）、失真（Total Harmonic Distortion）、阻抗（Impedance）進行實驗量測分析探討，並經由多次的實驗結果，驗證揚聲器表現。 This dissertation demonstrate the comparisons and analyses in the application frequency performance of speaker in the limited space by numerical analysis in NB (Notebook) and slim 3C products. In the analyses, measurements and numerical simulations are applied for further comparison to show the performances of speakers by LMS test system under ISO 3745 anechoic lab.To maintain the original sound pressure and space, the dissertation is dedicated to three contributions. 1. In the mathematics model of the speaker, using T-S parameter to simulate speaker unit and sound guide tube. And apply experiment and verification for the function. 2. To exchange the speaker in limited space to enhance the low frequency performance, instead of changing the speaker size and sound guide tube design in tradition. 3. Speakers can be reduced design, developing time and cost by this analysis process. In the experiment result, we found that starting vibration point in low frequency of original sound guide tube is 1300Hz. And the design of starting vibration point in low frequency in this experiment is 800Hz, which is 500Hz increase in low frequency performance. In the previous sound guide tube design, distortion performance decreases 10% after 800Hz. And this experiment leads to 10% decrease after 400Hz. We can hear the difference by music between these two designs clearly. Sound performance Q-value changed from 1.22 to 0.81 which is closed to the best performance in human hearing, which makes speaker design more easily than before.Regarding to the variation of the speaker in limited space, a series of analyses and actual experiments are conducted to prove the performance of speakers. Simultaneously, Sound Press, Total Harmonic Distortion and Impedance of speakers are measured and compared in the experiments, which can be regarded as indicators of speakers’ performances by several executive experiments.
