基于双全正弦的计算机乐器音色建模

Timbre Modeling of Computer Musical Instrument Based on Double-Total-Sine

提出了一种基于双全正弦的计算机乐器音色模型,以达到通过调节参数来改变计算机乐器音色的目的。该模型包括振动子模型和振幅包络子模型。保持了振幅包络参数取值不变,定义了调节音色的参数,分别为振幅系数、周期系数和方差系数。在VC++环境下,利用一维离散余弦变换获取该模型在不同参数下的频谱。通过分析音色参数对频谱的影响,找到这些参数对乐器音色的作用规律。实验表明,在振幅系数和周期系数都相等时,可将音高整体提高一个8度。在振幅系数和周期系数其中之一不等时,方差的值越大,音色的频谱就越丰富,乐器音色就越响亮;反之音色就越暗淡。对计算机乐器音色的合成和音乐的计算机生成具有一定的科学意义和实用价值。该模型简单,便于推广。

This paper presented a timbre model of computer musical instruments based on the double-total-sine, in order to make it possible that the instrument timbre can be controlled by modulating the parameters. This model includes two sub models, the vibration model and the amplitude envelope model. We made the parameter values of the amplitude envelope invariable during analyzing the model. We defined the timbre parameters, including the amplitude coefficient, the cycle coefficient and the variance coefficient. And we got the frequency spectrums of the model in different parameters using one dimensional discrete cosine transform in VC＋＋ environment. We found the rules of the parameters acting on the instrument timbre, by analyzing how the timbre parameters influence on the frequency spectrums. The experiments show that the total pitches can increase one octave if both the amplitude coefficient and the cycle coefficient are equal. And increasing the variance coefficient can make the frequency spectrums abundant, if one of the parameters, the amplitude coefficient and the cycle coefficient, is unequal; thus the instrument timbre is bright, contrarily the timbre is faint. So it is of important scientific significance and practical value for the timbre composition of computer musical instruments and the music generation by computer. This model is simple, so it can he popularized.