古琴音色仿真和变调技术的研究

Research of Stimulation and Pitch-scale Modification for GuQin Tamber

本文从古琴律制和音律学理论切入,描述古琴的音色特征,给出古琴音色仿真和变调的策略。通过基于LPA线性预测分析方法提取原始古琴音色预测系数,并基于对残差的自相关函数法搜索基音周期,根据基频合成激励谱后反滤波得到仿真音色,变调时用基频调整因子对残差序列进行线性插值,修改基频和共振峰频率实现古琴音色变调。实验结果表明,该方法能够有效的仿真出古琴音色并实现变调,在古琴音乐合成中具有很好的应用前景。

A method for GuQin timbre stimulation and timbre modification is introduced by describing the GuQin features,based on the theories of music and GuQin rules.The GuQin timbre stimulation is implemented by inverse filtering from the excitation spectrum synthesized by the GuQin pitch frequency,which is computed from residual signals by autocorrelation function method.The GuQin timber predictive coefficients are extracted from original GuQin sample signals using linear prediction analysis(LPA) method.Through linear interpolation on residual signals using adjustment parameters,GuQin timbre modification is implemented by correcting GuQin pitch and formant frequency.It has been proved that the method of timbre reconstruction is effective for GuQin timbre simulation and timbre modification,and would be applied in GuQin music synthesis well.