Electroacoustic processes based on time-frequency analyses and their application in live-electronic music

Abstract

This research project approaches theoretical and practical issues in composition, analysis and performance of live electroacoustic music, having as epistemological references the mode of existence of technical objects and the allagmatic method from Gilbert Simondon, besides the concept of enaction from Francisco Varela. Within electroacoustical processes, we analyze STFT processes (short time Fourier transform) of analysis and resynthesis of musical signals, based on time-frequency analyses, with a specific attention to convolution and phase vocoder. As analyses examples, we discuss the real time implementation of the source filter phase vocoder in Ressonâncias (2015), from Jônatas Manzolli, and also the implementation (by Arshia Cont), of the FFT pitch-shift in Anthèmes 2 (1997), from Pierre Boulez. Concerning musical composition, we will compose live electroacoustic music for different instrumental groups, applying the studied electroacoustic processes and computing tools. We will also manage the shifting of some characteristics of electroacoustic processes to instrumental writing. An analysis methodology about our compositional processes, based on audio descriptors, will be implemented, aiming to evaluate the sonic results and the need of changes in the musical writing and the numerical parameters of the electroacoustic processes. As theoretical basis for the analysis and composition, we approach the pre-audibility concept proposed by Gérard Grisey, the morphology of the musical time from Karlheinz Stockhausen, the discontinuity of musical scales from Horacio Vaggione and the catastrophe theory, saillances and prégnances from René Thom. We will search, through Thom's epistemology, to put together apparently antagonistic compositional thoughts, searching to conceive different interaction forms between objects, processes and temporal scales, conceiving them as belonging to a unique morphology, which in its interior can have both continuities and discontinuities. (AU)