Segmentation Methods in Electroacoustic Music:

Extracting Meso-Macro Structures for Acousmonium Performance

Abstract

This study proposes a reproducible segmentation procedure for fixed-media electroacoustic music, designed to support formal understanding during the preparatory phase of acousmonium performance. Its aim is not to develop an automatic, music-information-retrieval-style segmentation algorithm but rather to articulate an analyst-facing workflow whose decision steps can be replicated. The analysis is conducted in iAnalyse 5, a computer-assisted music analysis application that synchronizes multiple visualizations on a common time axis. Using iAnalyse 5, the waveform, spectrogram, self-similarity matrix (SSM), and brightness–spectral standard deviation (BStD) plot are aligned on a common time axis. From these synchronized visualizations, three types of sectional markers are extracted: Index (I), Boundary (B), and Transition (T). Candidate segmentation points are identified at times when at least two visual indicators exhibit concurrent changes; these points are then validated through focused listening immediately before and after each candidate position. This combined visual–aural verification is intended to privilege meso-level groupings over micro-level detail. This procedure is then applied to François Donato’s "Annam" as a case study. Track boundaries on the commercial compact disc (CD) release are treated as indices (I) provided by the medium, and additional Boundary (B) and Transition (T) markers are introduced to derive the meso-level segmentation (Segments 1–25) as well as the macro-level structure that consolidates these segments (Macro Sections M1–M5). The procedure superimposes I, B, T, meso-level, and macro-level layers onto a single timeline to reveal the relationship between divisions presented by the CD release and those inferred through listening and visual indicators. The results demonstrate that this integrated representation enables analysts and performers to grasp the meso–macro listening units required for acousmonium performance preparation.