Sointukulut

Sointukulut is a term used in Finnish music theory and computational musicology to describe a family of quantitative measures that assign a numerical “cost” to a chord or chord voicing within a musical context. The term combines sointu (chord) and kulut (costs). In practice, sointukulut are used to evaluate how suitable a chord is in a given progression, how easy it is for performers to voice, or how consonant or dissonant a voicing feels when heard with surrounding material. They are commonly employed in chord progression generation, voice-leading optimization, and automated arrangement.

Cost models typically include several components. Dissonance cost is based on the intervallic content and perceptual roughness of the chord. Voice-leading cost accounts for the amount and direction of melodic motion required to move from one chord to the next. Range and spacing constraints for individual voices help keep parts playable and balanced. Perceptual or stylistic preferences, such as favoring common tones or sparing wide leaps, may also be incorporated. Some models may penalize abrupt changes in timbre or register.

In pedagogy, sointukulut can be used to teach smoother harmonic progressions and better voice leading. In research, they provide a framework for comparing alternative harmonizations and for creating algorithmic compositions that optimize harmonic flow. The concept is used in various applications with differing emphasis depending on musical style and analytical goals.

See also: voice leading, harmonic analysis, chord progression, computational musicology.