Harmony

From the interval to the chord

The smallest harmonic unit is two tones sounding together, an interval. Some combinations sound calm and complete in themselves (consonant), others full of friction and asking for a continuation (dissonant). Neither is “better”: music lives on change, dissonance creates tension, consonance releases it. When three or more tones sound together, it is a chord. The basic building block is the triad; whether its third is major or minor decides between major and minor.

Functions

In a key, chords have functions: the tonic is home, the dominant creates tension and demands the return to the tonic, the subdominant leads away from rest and prepares the tension. A large part of all music is built from this, from the folk tune to the pop song. The remaining degrees act as substitutes. Functional theory goes back to Hugo Riemann.

Chord progressions

Just as tones become melodies, chords become chord progressions. The classic closing formula subdominant–dominant–tonic works like a sentence that ends meaningfully. From a few such building blocks whole songs can be accompanied. The circle of fifths shows which chords of a key are closely related. Harmony and melody are not side by side but together: the same melody over different chords changes its character, and a non-chord tone creates friction.

Common mistakes

• Confusing harmony with melody: Melody is the succession of tones, harmony their simultaneity.
• Pigeonholing major as “happy” and minor as “sad”: That is a rough rule of thumb, not a rule.
• Understanding the cadence as a duty: Some pieces deliberately leave the tension open.