Complain through the government hotline 12345. For the purpose of appeal, you must explicitly ask to remove the outdoor speakers of the barber shop, and then the city management will remove their stereos. If you can't do it once, complain a few more times. I am from Nanjing, and I succeeded.

People's Republic of China (PRC) Environmental Noise Pollution Prevention Act

Article 42 Commercial enterprises that use fixed equipment to conduct business activities in areas where noise-sensitive buildings are concentrated in urban areas and cause environmental noise pollution must, in accordance with the provisions of the competent administrative department of environmental protection of the State Council, report to the competent administrative department of environmental protection of the local people's government at or above the county level the status of the equipment that causes environmental noise pollution and the facilities for preventing and controlling environmental noise pollution.