There was an ancient saying - Lingering sound falls incessantly on the ears for three days.
This meant that if a person's voice was very pleasant to listen to, it would cause others to pause involuntarily as they felt reluctant to leave. Even if the voice stopped, their ears could still hear the lingering echo for many days.
When a great teacher's lecture was conducted perfectly, the effect of Lingering Sound would also occur. Students would feel reluctant to leave the classroom and yearned to continue listening.
Such a state was similar to when one ate a delicacy or drank an excellent brew.
When a great teacher had outstanding talent and had conducted many lectures that made students feel reluctant for the class to end, they would then comprehend Lingering Sound after a while.
Sun Mo carefully appreciated this great teacher halo. It didn't merely amplify his voice, but it would also cause his voice to be filled with magnetism.