Nature, Music, and Algorithmic Composition
Jeremy Leach, John Fitch · Computer Music Journal · 1995
puter that can use simple algorithms to automatically compose new pieces of music. The main theory in this article, which allows existing works to be analyzed in terms of tree structures, is reminiscent of the work by Fred Lerdahl and Ray Jackendoff (1983). However, we arrive at our event tree notion from a different fundamental stance. This theory, along with other new theories and methods in the analysis of music, are outlined in this article and embodied in an experimental software system for melody generation, XComposer. Previous attempts at musical analysis (Bent and Drabkin 1987) have often used tonal music as a base, making the resulting techniques inapplicable to other types of music. Such a technique was developed by Heinrich Schenker, who held that most musical works have a fundamental tonal structure embracing the whole composition. The Schenkerian technique reduces an original work to successive scores, each with fewer and fewer notes. Progression from one score to another involves grouping notes together and replacing each group by a single note. The final score, termed the background, contains one note that represents the work's fundamental tonal structure. Other analytic techniques include Roudolph Reti's Thematic Process, which tries to identify recurring non-rhythmic themes within a piece, and Hans Keller's Functional Analysis, which sees music as a constant battle between repeated themes and new information. All these forms of analysis could be used in reverse to synthesize certain elements of music. However, the analysis techniques lack generality, objectivity, and the ability to account for all the constructs that occur in music. (For example, how a e themes combined? Is it just a random process, or does it involve some kind of talent?) We believe that these problems will always exist in any analysis method that does not view music as something simple and fundamental. A critical look at some of the more obvious properties of music show what any analysis/resynthesis method should take into account.