"To appreciate the small, you can see the big, but there must be a lingering sound beyond the strings" means as follows:

Often because you can see the bigger things from the small things or principles. Feeling delighted, but also appreciating the subtext, that there are additional meanings and implications beyond the immediate understanding. In other words, it means that when understanding and appreciating things, we should not only see the small, medium and large on the surface, but also explore and appreciate the deeper meaning contained in them.

This verse is often used to describe the wisdom and aesthetic attitude of a deep understanding of things, encouraging people to see the larger world from a small perspective, while not forgetting to pay attention to the implication, that is, the implication.