This article describes the music data format of the recently introduced Sound Notation system, and how it makes possible computer-aided composition of scores representing sound-based music. The Sound Notation system is an adaptation of Lasse Thoresen's spectromorphological analysis notation, developed for composition and analysis. A detailed description of the data format is followed by two examples of its application in a computer-aided composition process resulting in the sounding interpretation of two score excerpts of an electroacoustic composition. Generating sound structures as symbolic notation data in this way provided possibilities for the creation of sound-based music otherwise limited to works of traditional notation.