常见的大钟有三种类别，唐朝时期的“平直形”钟口铜钟，唐宋时期的“浅波形”钟口铜钟，以及明清时期的“喇叭形”钟口铜钟。明清时期大钟的钟壁在钟口处都有外扩，呈现出所谓的“喇叭形”；铜钟的壁厚，由唐钟的均匀分布，演变为从上往下逐渐增厚，避免了早期大钟重击易裂的缺点。

There are three kinds of common bells: flat bell-mouth copper bell in Tang Dynasty, shallow waveform bell-mouth copper bell in Tang and Song Dynasty, and trumpet-shaped bell-mouth copper bell in Ming and zhagunmj.37ix.com.cnqiangban.37ix.com.cnshengtaimu.37ix.com.cnbianyaqigs.37ix.com.cn

mojuyz.37ix.com.cnmojulbs.37ix.com.cnQing Dynasties. In the Ming and Qing Dynasties, the bell wall of the bell expanded outside the bell mouth, showing the so-called "trumpet-shaped". The wall thickness of the copper bell changed from uniform distribution of the Tang bell to gradual thickening from top to bottom, avoiding the shortcomings of heavy hitting and cracking of the early bell.