電腦樂音合成對現代音樂創作，佔有重要的地位，音樂創作者利用電腦的便利性，可以快速而精準的控制要產生出的樂音。目前許多的研究在於樂器單音的合成，然而拉弦樂器和其他樂器最重要的區別，在於樂音轉折、變換時的表現；這是單音合成所難以達成的。在本文中，試著根據器樂曲錄音分析出更細膩的合成參數，讓樂音轉折、變換時的表現，得以重新合成出來。
我們實驗時以真實樂器錄音分析樂曲的合成參數，這些合成參數的決定過程中，又以基頻估測難度最高，而基頻估測在音訊處理上一直是重要的課題。文中，我們參考二胡的特性，亦針對基頻的估測，提出較準確的估測方法。

　　由於樂器的特性被記錄在音色庫中，與樂曲合成參數互相獨立，因此我們可以將演奏手法經分析後轉換成對應的合成參數，然後使用不同音色庫做合成；如此的作法，相當於用另一種樂器來演奏原來的樂曲，並且還能保留住原本的演奏手法。

　Synthesizing musical sound plays an important role on modern music composition for decades. Music composer nowadays can easily take advantages of powerful and user-friendly personal computers to produce his/her desired musical sound. A lot of music synthesis researches focuses on synthesizing a single note of an instrument. However, the bowed stringed instruments are very different from other instruments in their expression. This kind of expression is not achievable by single-tone synthesis. In this article, we try to analyze the correspondent recordings to describe more exquisite synthetic parameters which allow us to reproduce the varying expressions.
In our experiments, the instrumental recordings were carefully analyzed and extracted several appropriate synthetic parameters are extracted. Among those parameters, detecting and tracing the fundamental frequency (pitch) is one of the most difficult problems. The pitch detection is a classical issue in the audio processing field. In this article, we consider some characteristics of Erhu and propose an accurate pitch estimation method.

　Since the sound bank recording the characteristics of musical instruments is independent of the melody synthetic parameters, we can synthesize the musical expressions by the melody parameters in cooperated with the sound banks. In other words, it seems that we play the original melody with a different instrument and keep the original musical expressions.

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