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IJMSTA - Vol. 3 - Issue 2 - July 2021
ISSN 2612-2146
Pages: 38
Igicunda: the drum that keeps the rhythm. Onset detection and spectral analysis of African drum patterns
Authors: Dominik Phyfferoen
Categories: Journal
Abstract - In this paper we present some results of the rhythmic analysis we conducted on the dance song Igicunda of Rwanda. To realize this, we implemented during the structural analysis on the historical field recording, a wide range of different types of methods and techniques such as rhythmic onset detection, spectral analysis in combination with manual score annotation techniques and an audio sound synthesis of the annotated dance song. The audio synthesis of the annotated score notation was done using midi-code in combination with the real-audio of the field recording. Our analysis model consists of two parallel tracks that complement each other. On the one hand, we used a standard manual score notation analysis that shows the general structure of the dance song, combined, and supplemented with cyclic rhythmic annotation techniques to analyse the drum patterns and the handclaps in the dance song. On the other hand, to extract the cyclic drum patterns and the handclaps out of the audio signal, we implemented on a section of the audio field recording an onset detection, in combination with a spectral decomposition of the tone complex. Later, we conducted a dynamic data-driven audio analysis using rhythmic onset detection and a rhythmic algorithm. Both signals were subjected to the analysis. The result was a perfect match for both the rhythmic analysis of the ingoma drum pattern and the handclaps, as for the hochetus singing style of the leading cantor and the call and response of the choir. During the analysis we were able to extract several structural key components out of the audio signal belonging to the traditional idioms of music-making e.g., homeostasis states, transitional states, state transitions, free rubato rhythms, call and response singing style, hochetus singing style, frequency modulation and the tempo stability factor. With this paper, we aim to contribute to the ongoing discourse on the study of polyrhythms in African musical traditions and to illuminate on its relationship to music-making in the traditional idioms, this from the research paradigm embodied music interaction and expressive timing. So far, we can present a working model that allows us to detect and extract complex rhythmic patterns from African music. Our analysis model shows that traditional score annotation techniques and rhythmic cyclic annotation in combination with onset detection and sound synthesis of the audio signal is a solid and powerful method to analyze and present traditional music and dance in Africa on a rhythmic level. We hope that our contribution can inspire and encourage teachers and students in African Studies to gain a deeper understanding and inside of the richness of the traditional idioms of music-making among African music cultures.
Keywords: African Studies, Ethnomusicology, Onset detection, Timeline patterns, Rhythmical architypes, Homeostasis states, State transitions, Transitional states
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