Musicians interested in improvising melodies often benefit from the ability to analyze chord progressions for tonality and from possession of an understanding of a range of idiomatic chord progressions. We describe automated analysis using an approach to representing idioms known as “bricks,” which can also be used in analysis of tonality. The brick nomenclature is attributed to Conrad Cork's “Lego Bricks” approach, as extended by John Elliott. We demonstrate a semi-automatic grammatical approach to analysis of chord sequences and sketch its implementation, which is available in the form of free, open-source software called Impro-Visor.

Music scholars have been studying tonal harmony intensively for centuries, yielding numerous theories and models. Unfortunately, a large number of these theories are formulated in a rather informal fashion and lack mathematical precision. In this article we present HarmTrace, a functional model of Western tonal harmony that builds on well-known theories of tonal harmony. In contrast to other approaches that remain purely theoretical, we present an implemented system that is evaluated empirically. Given a sequence of symbolic chord labels, HarmTrace automatically derives the harmonic relations between chords. For this, we use advanced functional programming techniques that are uniquely available in the Haskell programming language. We show that our system is fast, easy to modify and maintain, robust against noisy data, and that its harmonic analyses comply with Western tonal harmony theory.