《国语·周语·景王问钟律于伶州鸠》
音声高细的乐调中有钟而无镈，是要显示钟声的低弘；在音声低弘的乐调中有镈而无钟，更低的乐调中连镈都没有，是要表现弦乐的悠扬。
细钧有钟无镈，昭其大也。大钧有镈无钟，甚大无镈，鸣其细也。
In tunes with high and fine pitch, the bell is present but the gong is not in order to demonstrate the deep and rich tone of the bell. In tunes with low and rich pitch, the gong is present but the bell is not, and in even lower tunes, there isn't even a gong, in order to display the lingering tone of the strings.