Decay Music is the 1976 debut album by Michael Nyman, released on Brian Eno's Obscure Records music label. The two works on the album, 1-100 (composed 1 December 1975) and Bell Set No. 1 (1974) are both built around the musical concept of decay. Both of these experiment with percussive, long decay musical forms. 1-100 is played at half the speed it was recorded. It was written for Peter Greenaway's film of the same title, but rejected because it was too long.