於嘈雜環境下，使用者操作資料讀取器時，常會有聽不見信號聲的情形，以至於無法判斷資料讀取器是否已正確讀入。為了改善此情況，本研究利用聲學軟體進行模擬分析，並以之引導實驗之進行。研究結果證實將出音孔位置移至整機後方確實能有所改善，但使用導音管與反射板則無法解決音量不足之問題。
本研究在揚聲器單體前方與後方分別加上一空腔，探討開放式之前音腔、密閉式之後音腔與具有洩漏面積的前腔蓋板之組合如何能使音量提高。研究結果顯示，設計時必須於揚聲器後方加上一密閉式之後音腔，即可在低頻區出現一峯值，後音腔體積之增加能使峯值之頻率降低，且音量會略微上升；若同時加上前音腔與後音腔，則前音腔體積之增加會影響後音腔所產生的峯值之頻率，但不影響其音量大小；減少前腔蓋板之洩漏面積亦會使峯值之頻率降低，且會使音量大幅增加。由上可知，設計時必須適當組合此三項參數，先利用前/後音腔之體積調整峯值之頻率，再善用前腔蓋板之洩漏面積來提高音量。而改變前腔蓋板之洩漏孔形式亦可略微影響峯值之頻率達±250 Hz。最後根據這些設計準則做一實例設計，發現可將目標頻率之音量較僅有揚聲器時增加約25 dB(A)。

In a noisy environment, the user frequently can not hear the signal sound when operating a data reader. Thus, the user can not judge whether or not the data reader has correctly read data. In order to solve this problem, this study used software to simulate and analyze the situation.
Research results showed that placing the speaker to the rear end of the data reader can positively increase the sound level. But using the sound guiding tube or reflecting boards can’t help the real situation.
This research studied how a closed-ended rear cavity and a front cavity with limited openings can increase the sound level of a mini-speaker. Research results showed that a closed-ended rear cavity would generate a sound peak in the frequency spectrum. The larger its volume is, the lower the peak frequency and also a lighter increase on the peak value would be. Also, a larger open-ended front cavity would lower the frequency of the abovementioned peak further. In addition, a cap with limited opening on the front cavity can not only lower the peak frequency but also increase the peak value substantially if the area of openings is smaller. Also, different arrangements of the tiny opening holes can affect the frequency of the peak by ±250 Hz. Finally, a simulated example indicated that a good combination of all these design parameters can effectively raise the volume of such a mini-speaker by 25 dB(A).

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