Speaker
Description
Playing techniques from African-rooted percussion instruments focus on exploring the range of sounds produced by striking different parts of the membrane with different parts of the hitting hand. This creates a sonic palette through which culture-defining rhythms are performed. However, the perceptual descriptions found in the literature are usually limited to language metaphors with no clear acoustic correlation, endangering the preservation of such immaterial cultural heritage and exposing the need for accurate psychoacoustic characterizations. In the present study, I explore the use of phase space embedding, correlation dimension and Lyapunov exponents as psychoacoustic descriptors suited for playing technique description. The analysis is grounded in the relation between the short duration of the instrument's transients, the stationarity conditions required for the analysis of time series as well as the constraints they impose regarding sampling rate and signal length; and the temporal windows for auditory processing of timbre and pitch established in the literature. Samples from three different playing techniques (bass, slap and open) performed in the Ghanaian Djembe, the Brazilian Atabaque and the Colombian Alegre —African-rooted single-headed wooden vessel drums— are investigated, systematically varying the parameter settings employed for their projection in the phase space. For each derived embedding, the resulting descriptor values are presented; the gathered results are then examined to assess the influence of the embedding parameters on their calculation and psychoacoustic interpretation in light of the playing techniques. This study is thus a first step toward a psychoacoustic description capable of grounding the digital preservation of playing technique diversity against processes of cultural homogenization.