Interactive electroacoustic music that alters or extends instrumental timbre, samples it, or generates sound based upon data generated in real time by the performer presents a new set of challenges for the performing musician. Unlike tape music, interactive music can continuously vary its response and, frequently, performers are unable are to predict how the computer will react. Many, if not most, scores include no visual representation of how the computer may affect the sound of the instrument.

Providing performers with a readily accessible visual representation of the sonic possibilities of interactive computer music will provide a conceptual framework within which performers can understand a piece of music. Interpretation of this type of notation by the performer will provide a perspective on how his or her acoustic instrument relates to the digital instrument. This can be especially useful when improvised or aleatoric methods are called for.

This paper outlines a system of interactive computer-music descriptive notation that links pictographic representations to the system of spectromorphologies suggested by Dennis Smalley. The morphological notation (MN) uses these morphologies and adds a z-plane to the well-established time-vs-pitch schema. Ideally, MN will not only represent the sound data of the moment, but also will be an intuitive picture of the musical possibilities of a composition's electronic component.