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題 名 | 琵琶音樑對面板振動模態及聲音頻譜之影響=Influence of Pipa Bass Bars on the Vibration Modes of Top Plate and Sound Spectrum |
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作 者 | 魏仲濱; 陳國華; 陳周宏; | 書刊名 | 林產工業 |
卷 期 | 26:4 2007.12[民96.12] |
頁 次 | 頁255-266 |
分類號 | 436.187、436.187 |
關鍵詞 | 琵琶; 音樑; 面板; 振動模態; 包絡線; 聲音頻譜; Pipa; Bass bar; Top plate; Vibration mode; Envelope; Sound spectrum; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究針對琵琶音樑進行不同配置的探討。希望以科學性、系統化的量測,了解琵琶面板的振動模態。最後比較黏貼不同形式音樑的琵琶成品,彈奏並錄音,分析其頻譜,以印證音樑改革之可能性,並解釋其合理性。經由本研究獲得結論:(1)支點位置的不同產生的克拉尼圖案亦異,由此可推論樂器內的樑柱位置及大小會影響振動模態,進而影響音色、音量等。(2)梨形面板支點在全長1/3處反應明顯,且高頻仍有共振產生,所以目前的琵琶製作將橫向音樑浮貼在全長1/3處上面,是合理而且可產生較好共振的。(3)梨形面板支點於1/3處,140 Hz頻率的克拉尼圖案於橫向1/4處產生縱向節線。因此,在這個位置可黏貼縱向音樑。(4)貼縱向音樑比貼橫向音樑較快產生節線,且激發的模態也較多,到高頻也會產生,基本上縱向音樑應是較橫向音樑利於傳振。(5)從包絡線圖可以發現貼縱向音樑的琵琶四條弦的空弦音及六弦音,均衰減的比較快,即餘韻較短。(6)由包絡線及頻譜分析比較分音強度,縱向音樑琵琶的第1分音(基音)均比橫向音樑的強度大很多,所以聽起來較大聲,而相對的,第2、3、4、5分音強度則較小,造成音色較空。從包絡線圖中則發現殘響餘韻較短。 |
英文摘要 | This study focused on the acoustical properties of the Pipa top plates with different bass bars disposition. It was intended to understand the vibration mode of Pipa top plate by using scientific and systematic measurement, to compare the Pipa with different styles of bass bar, to play, record, and analyze its spectrum, to prove and explain its rational innovation. The major findings are listed as follows: (1) The different suspension system got different Chladni pattern mode, so the position and size of bass bar in the instrument would affect the modes of vibration, and also had the influence on timbre or sound volume. (2) The reaction of pear plate supported at one third position was very clear, and while high frequency still had resonance, so it was a good reason for put the bass bar at the one third position of Pipa top plate, it got better resonance. (3) The Chladni patterns of the pear shape plate produce d vertical node line in 140 Hz at one forth position in horizontal direction, with support at one third position. So, vertical bass bar could be pasted there. (4) The node line of top plate with vertical bass bar was more quickly produced than with horizontal bass bar, and excited more modes, and continued to high frequency. Basically, vibration transmission of bass bar, the vertical one is better than that of horizontal one. (5) From the envelope, sounds played in the four open strings and the sixth fret of Pipa are decaying faster than other fret when the vertical bass bar is used. (6) After comparing the harmonic strength by envelope and spectrum, the plates with vertical bass bar have stronger and louder fundamental sound and softer 2nd to 5th harmonics in dB than those of plates with horizontal bar. Its residual time is shorter in the figure of envelope. |
本系統中英文摘要資訊取自各篇刊載內容。