AutoChorusCreator: Four-Part Chorus Generator with Musical Feature Control, Using Search Spaces Constructed from Rules of Music Theory

This paper describes AutoChorusCreator(ACC), a system capable of producing, in real-time, a variety of fourpart harmonies from lead sheet music. Current algorithms for generating four-part harmony have established a high standard in producing results following rules of harmony theories. However, it is still a challenging task to increase variation in the output. Detailed constraints for describing musical variation tend to complicate the rules and methods used to search for a solution. Reducing constraints to gain degrees of freedom in variation often lead to generating outputs which do not follow the rules of harmony theories. Our system ACC is based on a novel approach of generating four-part harmony with variations by incorporating two algorithms, statistical rule application and dynamic programming. This dual implementation enables the system to gain the positive aspects of both algorithms. Evaluations indicate that ACC is capable of generating four-part harmony arrangements of lead-music in realtime. We also confirmed that ACC achieved generating outputs with variations without neglecting to fulfil rules of harmony theories.