The Great music Orchestra is a large-size orchestra of the Viet ethnic group. It was only played when the king was present in great ceremony like General Court, the King’s birth day ceremony, heaven-worshipping ceremony, Foreign ambassador reception etc. and other national worshipping ceremonies of great importance, such as Giao (the Sky and the Earth) worshipping ceremony, Tich Dien ceremony (when the King himself ploughed), etc. The orchestra includes twenty big drums, eight wind instruments, four horns made of buffalo's horn and two horns made of shellfish. The powerful volume created by percussion instruments and aerophones in the orchestra can create solemn in the royal ceremonies.