This was an important celebration. Any big celebration calls for music. So the King assembled A great Orchestra. They rehearsed and practiced. There would be Lots of music.
World likes to make sin and idolatry look so attractive and fun.
The most important music they would play would be the signal for everyone to bow down. The King would watch from his pavilion as they did. For the King was Worried about disloyalty. He was still bothered by His dream. His kingdom could fall.