《宋书·志·卷十一》
《周语》中说： 黄钟传播培养六气九德。 正声声调的规定，以黄钟为宫声，这样姑洗就是角声。
正声调法，黄钟为宫，应钟为变宫，南吕为羽，林钟为徵，蕤宾为变徵，姑洗为角，太蔟为商。
<Zhouyu> says: Huangzhong spreads and nurtures six qi nine virtues. The regulation of the correct sound and tone, with Huangzhong as the palace sound, thus Guxi is the angle sound.