Goiaba: a software to process musical contours Marcos S. Sampaio 1 , Pedro Kr¨ oger 1 1 Genos—Grupo de pesquisa em Computac ¸˜ ao Musical Escola de M ´ usica da Universidade Federal da Bahia mdsmus@gmail.com, pedro.kroger@gmail.com Abstract. Contour is the shape or format of objects. Contours can be associated to musical parameters such as pitch and time, representing one in function of another. Contours help to give coherence to musical piece and can be used to analyze and to compose music. Contour theories provide many operations that demand precise mathematical calculation. In this article we present the current state of Goiaba, a software that assists musicians in contour related tasks such as the calculation and plotting of operations, and a case study of a composition where Goiaba was used to generate the contour-related material. 1. Introduction Contour is the shape or format of an object. In music one can speak of a pitch contour, density contour, and so on. Contours can easily be recognized from graphic representation by professionals and laymen alike [Marvin, 1988]. For instance, Beethoven’s Fifth Sym- phony’s main motive and the corresponding pitch contour are represented respectively in figures 1a and 1b.   4 2                (a) Main motive 0 1 2 3 0 1 2 3 pitch time (b) Contour F(3 1 2 0) Figure 1: Fifth Symphony main motive contour Technically, a contour is an ordered set of numbered elements [Morris, 1993]. Ab- solute values of contour elements are ignored, and only the high-low relationship between them is regarded. For instance, the music in figures 1a and 2 have the same pitch contour, graphically represented in figure 1b, and symbolically by F(3 1 2 0) 1 . Yet, both passages sound completely different. In our opinion that is a feature of using contour theory in composition, to have an underlining process providing coherence and musical variety at the same time. The study of contour is important because contours can help to give coherence to a musical piece, like motives and pitch sets. They are structural devices that can be combined through operations like inversion and retrogradation, and can be approached by analytical or compositional points of view. 1 The uppercase letter F names the contour.