Discovering Chord Idioms Through Beatles and Real Book Songs

Modern collections of symbolic and audio music content provide unprecedented possibilities for musicological research, but traditional qualitative evaluation methods cannot realistically cope with such amounts of data. We are interested in harmonic analysis and propose key-independent chord idioms derived from a bottom-up analysis of musical data as a new subject of musicological interest. In order to motivate future research on audio chord idioms and on probabilistic models of harmony we perform a quantitative study of chord progressions in two popular music collections. In particular, we extract common subsequences of chord classes from symbolic data, independent of key and context, and order them by frequency of occurrence, thus enabling us to identify chord idioms. We make musicological observations on selected chord idioms from the collections.