Minecraft wiki entry for Note_Block, associated text: Note blocks play a musical note when hit (pressing use) or when powered by redstone. A note block must have air in the space directly above it to play a sound. Notes can be heard up to 48 blocks away. The volume of a note block decreases as the player gets further away from it. The sound of note blocks (as well as jukeboxes) can be independently controlled by the Jukebox/Note Blocks slider in the audio settings.