The concept establishes that Western tonal theory necessitates three distinct minor scale variations—natural, harmonic, and melodic—to resolve functional deficiencies inherent in the natural form regarding voice leading tension and root dominance. The theoretical mechanism operates by manipulating specific diatonic intervals (specifically raising the sixth and seventh degrees) to alter chord qualities within associated harmony; specifically, the augmented interval between the raised sixth and original seventh in the harmonic minor creates an unstable sonority that necessitates further modification in the melodic ascent to establish a leading tone while eliminating large leaps. Consequently, these variations serve as formalized mechanisms for generating specific harmonic progressions, particularly major subdominant functions (V chords) within minor keys through the application of altered scale degrees during vertical chord construction and horizontal voice leading.
The concept establishes that Western tonal theory necessitates three distinct minor scale variations—natural, harmonic, and melodic—to resolve functional deficiencies inherent in the natural form reg…