《史记·八书·乐书》
因此，被物所感而生哀痛心情时，其声急促而且由高而低，由强而弱；心生欢乐时，其声舒慢而宽缓；心生喜悦的时候，其声发扬而且轻散；心生愤怒时，其声粗猛严厉；心生敬意时，其声正直清亮；心生爱意时，其声柔和动听。
是故其哀心感者，其声噍以杀；其乐心感者，其声啴以缓；其喜心感者，其声发以散；其怒心感者，其声粗以厉；其敬心感者，其声直以廉；其爱心感者，其声和以柔。
Therefore, when a person feels sad due to the impact of external objects, his voice becomes urgent and low from high, and from strong to weak; when his heart is happy, his voice becomes leisurely but slowly; when his heart is full of joy, his voice becomes exaggerated and scattered; when his heart is full of anger, his voice becomes rough and severe; when his heart is full of respect, his voice becomes upright and clear; when his heart is full of love, his voice becomes soft and beautiful.