《宋书·志·卷十一》
这样就命令部郎刘秀、塑昱、旦艳、魏塑等人与笛工共同去制笛，工人负责制作，管音律的人确定其声音对应的音律，从而做到乐器规格有明确的规定，它的声音作为均也就协调了。
辄令部郎刘秀、邓昊、魏邵等与笛工参共作笛。工人造其形，律者定其声，然后器象有制，音均和协。
Thus orders were given to Liu Xiu, Su Yu, Dan Yan, Wei Su and others in the Ministry to work together with the flute maker. The worker would make the flute, and the person who understood scales would regulate the notes, so as to ensure the standard of the instrument. As the standard, its notes would be harmonious.