Melody and Harmony
Senior 2 · Music
Melody and Harmony
Lesson 2 of 5
25 min
Sing a melody alone and you hear one line. Now imagine a guitarist strumming under your voice, or a choir singing four different notes at once. The music suddenly sounds fuller and richer. That extra layer is harmony. Melody moves across the page, one note after another; harmony stacks notes up the page, sounding together.
Nearly every song you know, from church hymns to Afrobeats, is built on a few simple chords. In this lesson you learn how those chords are made and which ones belong to a major key.
The rule works from any note: take every other letter name. From F you get F A C; from G you get G B D.
Triads sound different because of the size of their thirds. Count semitones (the smallest step on a keyboard, from one key to the very next, black or white):
| Type | Root to third | Third to fifth | Example | Sound |
|---|---|---|---|---|
| Major | 4 semitones | 3 semitones | C E G | bright, settled |
| Minor | 3 semitones | 4 semitones | D F A | darker, softer |
| Diminished | 3 semitones | 3 semitones | B D F | tense, unstable |
Check C E G: C to E is C, C♯, D, D♯, E, that is 4 semitones; E to G is E, F, F♯, G, 3 semitones. So C E G is major.
Build a triad on each of the seven notes of C major, using only notes of the scale, and you get the seven chords of the key. Musicians number them with Roman numerals: capital letters for major triads, small letters for minor ones, and a small circle (°) for the diminished one.
The pattern is the same in every major key: I ii iii IV V vi vii°.
Chords I (the tonic), IV (the subdominant) and V (the dominant) are called the primary triads. They are all major, and between them they contain every note of the scale. Check in C major: C E G + F A C + G B D gives C, D, E, F, G, A and B. That is why a musician who knows only these three chords can accompany a huge number of songs.
| Key | I (d m s) | IV (f l d') | V (s t r') |
|---|---|---|---|
| C major | C E G | F A C | G B D |
| G major | G B D | C E G | D F♯ A |
| F major | F A C | B♭ D F | C E G |
| D major | D F♯ A | G B D | A C♯ E |
Notice that the same triad can appear in several keys with a different number. C E G is chord I in C major, chord IV in G major and chord V in F major.
Tip
Every other letter, on d, f and s. To spell a triad, take every other letter name from the root. To find the primary triads of any major key, build triads on the 1st, 4th and 5th notes of its scale: doh, fah and soh. Remember to keep the key's sharps or flats: in G major, chord V is D F♯ A, not D F A.
Spell the triads on D and on A in C major, and say whether each is major or minor.
Solution: D F A and A C E. D to F is 3 semitones (D, D♯, E, F), so D F A is minor (chord ii). A to C is 3 semitones too, so A C E is minor (chord vi).
Write the primary triads of G major.
Solution: the G major scale is G A B C D E F♯. Triads on the 1st, 4th and 5th notes: I = G B D, IV = C E G, V = D F♯ A.
A melody in C major has a long note B. Which primary triad contains B?
Solution: only V (G B D). Chord I is C E G and chord IV is F A C, and neither contains B.
Is C E G B a triad? Explain.
Solution: no. A triad has exactly three notes. C E G B has four: a C major triad with a seventh (B) added on top.
Remember
Sources and credits
The notation drawings, tables, worked examples and practice were written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
