This article explores new approaches for notating the morphology of sound using the framework of CS Peirce’s concept of indexical signs. While pictographic and symbolic notation struggle to notate the lived dynamic experience of music, indexical notation offers new possibilities for attending to the material, temporal and spectral flux of sound. Drawing from theories outlined by Floris Schuiling, this article presents a case study of an interactive score titled Undersong1 for solo performer that eschews symbolic or pictographic notation in favour of establishing indexical causal relationships between performer and visual responses. The case study suggests that indexical signs may offer an accessible way to engage performers with spectral and morphological elements of sound, opening new pathways for notation to engage experiential phenomena.
