《明史·志·卷三十七》
所以用黄钟为羽，必定用子声，就是上黄六的清声，正是不敢用黄钟全声，而用其半的原因。
所以用黄钟为羽，必用子声，即上黄六之清声，正为不敢用黄钟全声，而用其半耳。
Therefore, when Huangzhong is used as Yu, Zi Sheng must be used, which is the clear sound of Shang Huang Liu. It is because he dared not use the full sound of Huangzhong but used half of it.