《太平广记·卷二百零五·乐三》
德宗皇帝又让乐工们演奏，一曲终了，询问宋沇：这次他们演奏得有什么长处与错误的地方？
上又使作乐，曲罢，问其得失，承禀舒迟，众工多笑之。
Emperor Dezong asked the musicians to play again; after a piece of music, he asked Song Yan: What are the strengths and flaws in their performance?