- 期刊
CNC製作小提琴面板之音響分析
Acoustic Analysis of Violin Panel Processed by Computer Numerical Control
摘要
小提琴對於西方世界來說，是一種很重要的演奏樂器。小提琴不僅在樂團中有其重要位置，在手工藝的表現上也甚有成就。從小提琴的成品可以看出一位製琴家的手藝以及其音樂的素養，因此小提琴一直到現在都需要靠著製琴師的手一刀一刀的刻劃出來。但如今的科技發達，工業技術也越來越進步，應能藉由自動化機械CNC（Computer Numerical Control電腦數值控制）來縮短提琴的製作時間；並藉由檢驗各種材料的聲音振動特性以瞭解其品質，考慮提琴的可能替代材料，是為本文的主要探討焦點，經試驗結果如下：（1）以聲音傳導特性而言，雲杉雖縱向聲速較低而橫向聲速稍高，因而異方性較小。纖維板則音響性較差。（2）面板的加工程度越高，質量越輕，比較容易引起振動。整體而言，殼狀板主峰的出現位置比凸狀板更偏向低頻區，此表示質量輕者，越容易有共振的現象出現，但其共振的持續力不如質量重者。部份頻率振幅之衰減是造成波峰之聲音清晰的因素之一。（3）殼狀面板支撐方式的振動頻率分析中，四點支撐的主峰區有些微的分散而中線支撐中除了一塊花旗松特別敏銳之外，兩者之間無太大的差異。（4）雲杉的振動頻率測試主峰比其他者高而響，整個振幅位準dB都維持稍高；貝殼杉與雲杉比重相近，振幅反應相近；花旗松則在各階段有明顯區別；至於單片的取材或對稱拼板而成的，則無明顯區別。
並列摘要
The violin is a kind of very important musical instrument to the Western countries. Violins have an important position in the orchestra, its representation in the handicraft is also very successful. We can find out the accomplishment of craftsmanship and its musical equipment of the maker from the finished product of the violin, so far, violin still needs the maker to carve one after another very carefully. But today the science and technology is well developed, the industrial technology progresses very rapidly, we should be able to shorten the making time of the violin with automatic machinery CNC (Computer Numerical Control); And by examining the vibration characteristics of sound of different materials in order to understand its quality, does the violin have suitable substituting materials? It is the main focal point of this paper, the results of the test are as follows: (1)The characteristic of the conductivity of sound, although spruce is lower on the vertical sound velocity but horizontal sound velocity is slightly higher, so anisotropy is smaller. The fiberboard stereo is relatively bad. (2)The higher the processing degree of the panel is, the lighter mass is, and more easy to cause vibration. As a whole, the appearing position of the highest peak of convex board of shell has the tendency towards the low frequency district than the convex board, indicates that this express quality the lighter, panel easy to have the phenomenon of resonance, but the lasting tune of resonance is not as good as the heavy panel. The amplitude decay of some frequency is one of the sound clear factors for the crest. (3)In the vibration frequency related to the shell form panel supports is analyzed. District disperse slightly in highest peak that supporting in four-point, and there is no significant difference with centre line except one piece of Douglas fir, which has sharp vibration frequency supported at centerline. (4)The main peak of vibration frequency of spruce is higher and louder than the other one, allows dB to keep slightly high in the whole amplitude location; The shell Agathis is similar to proportion of the spruce, the amplitude is close in response; There is significant difference at every stage in the Douglas fir; There is no obvious difference between symmetrical makeup or single slice plate.