This project consists of an original composition, Voci Lontani, and a critical essay about the composition. In this piece, the idea of musical simultaneity is explored. Therefore, the piece focuses on the idea of contrast: between measured rhythms and indeterminate rhythms, between tonality and atonality, and between musics in separate tempos. In order to explore the significance of musical simultaneity, four important compositional concepts-the simultaneous juxtaposition of different musics, polyrhythmic structure, controlled indeterminacy, and quotation-are discussed. Also, several examples of twentieth-century music that use these concepts are analyzed in the essay.