An Evolutionary Approach Applied to Algorithmic Composition Jônatas Manzolli – jonatas@nics.unicamp.br University of Campinas – Interdisciplinary Nucleus of Sound Communication – UNICAMP/NICS Artemis Moroni – artemis@ia.cti.br Technological Center for Informatics – The Automation Institute - CTI/IA Fernando Von Zuben – vonzuben@dca.fee.unicamp.br University of Campinas – Electric Engineer Faculty - UNICAMP/FEE Ricardo Gudwin – gudwin@dca.fee.unicamp.br University of Campinas – Electric Engineer Faculty - UNICAMP/FEE Abstract This paper presents an end- user interface that allows real time parametric control of sound events resulting in an interactive environment, in which Evolutionary Computation is applied to Algorithmic Composition. The resulting system, Vox Populi, uses genetic algorithms to generate and evaluate a sequence of chords played as MIDI data. Harmonic, tonal and voice range fitness are used to control musical features. Based on the ordering of consonance of musical intervals, the notion of approximating a sequence of notes to its harmonically compatible note or tonal centre is used. This method employs fuzzy formalism and is posed as an optimisation approach based on factors relevant to hearing music . 1 I NTRODUCTION Evolutionary Computation has been successfully applied to control music processes. An application of genetic algorithms to generate Jazz solos is described in (Biles, 1994) and this technique has also been studied as a way of controlling rhythmic structures (Horovitz, 1994).