《宋书·志·卷十五》
所以汉文帝安葬之后，全都恢复行吉礼，衹是悬挂钟磬乐器而不奏乐曲，以这样的处理来表示哀伤。
故汉文既葬，悉皆复吉，唯县而不乐，以此表哀。
So after emperor Wendi was buried, everything had returned to normal, but bells and chimes were hanged but not played, this was done to show grief.