This article 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 posited as an optimisation approach based on factors relevant to hearing music.