When did the ancient music in China disappear?

I wonder if China's music has been lost. However, China's classical culture has lost a lot in thousands of years.

The main reasons are the invasion of foreign culture, war and the intentional action of the ruling class.

1. The history of China is actually a process of invasion, integration and assimilation by northern nationalities. From the Qin Dynasty's unification of China to the Wu Rebellion and then to the Yuan and Qing Dynasties. New cultures are constantly merging. In this way, the original thing is diluted.

Every war has caused cultural loss. This is a lot. Look for a pile in the history books.

The ruling class did this on purpose. The book of Qin dynasty burned, and the book of Qing dynasty was repaired. Every time the injury is serious.