The Huyen orchestra occurred in the 19th year of the Minh Mang dynasty (1838) and was used in worshipping ceremony, such as Thanh Tho ceremony, Van Tho ceremony, Thien Xuan ceremony, heaven-worshipping ceremony (When king appearing and coming to a platform). The orchestra includes one big musical stone, one set of 12 small musical stones Bien khanh, one big bell, a set of 12 small bells Bien chung, one big drum, one small drum, one two-sided drum, one trough-shaped wooden box chuc, one wooden tiger ngu, two castanets, two long board zither dan cam, two zithers dan sat, two vertical flutes, two transversal flutes, two ocarinas huan, two transversal flutes tri, two mouth organs sinh.