Before revision: For playback of 5.1 music, the International Telecommunication Union (ITU) recommends the following configuration (ITU-R BS 775): five speakers of the same size for front, center and surround identical distance from the listeners for all five speakers angle adjustment regarding viewing direction of audience: center 0°, front ±22.5° for movies ±30° for music, surround ±110
After revision: Speaker Placement For playback the International Telecommunication Union (ITU) recommends the following configuration (ITU-R BS 775): five speakers of the same size for front, center and surround identical distance from the listeners for all five speakers angle adjustment regarding viewing direction of audience: center 0°, front ±22.5° for movies ±30° for music, surround ±110