Chord Complexity
Chord Complexity tracks when a song goes beyond simple three-note chords—either by adding extra tones (like 7ths or add9s) or by borrowing notes from outside the key—creating richer, more sophisticated harmonies.
Melodic Complexity
Melodic Complexity reflects two factors: the use of notes outside the key and rhythmic syncopation, together capturing how intricate or surprising a melody feels.
Chord-Melody Tension
Chord-Melody Tension quantifies how often melody notes fall outside the current chord, producing dissonance that creates a sense of instability.
Chord Progression Novelty
Chord Progression Novelty measures how uncommon a song's chord changes are compared to others in the Hooktheory database, highlighting progressions that deviate from typical patterns.
Chord-Bass Melody
Chord–Bass Melody evaluates how smoothly the bass moves between chords, scoring higher when it travels step-wise, ascending or descending, instead of jumping directly between root position chords.