# Harmony Basics — Music Knowledge

> Chord theory simplified for songwriting and prompt engineering.

## What is harmony

Harmony = multiple notes played simultaneously. Chord = 3+ notes together.

## Chord types

### Major
Bright, happy, stable. C-E-G in C major.

### Minor
Sad, melancholic, introspective. C-Eb-G in C minor.

### 7th chords
Add tension. Common in jazz, R&B, soul.
- Major 7 (e.g., Cmaj7) — dreamy, jazzy
- Minor 7 (e.g., Cm7) — soulful, mellow
- Dominant 7 (e.g., C7) — bluesy, tense

### Suspended (sus)
Floating, unresolved. Often resolves to major.

### Augmented / Diminished
Tense, unstable. Used for dramatic moments.

## Diatonic chords (in a key)

In C major:
- I = C major (tonic, home)
- ii = D minor
- iii = E minor
- IV = F major (subdominant, lift)
- V = G major (dominant, tension)
- vi = A minor (relative minor, sad)
- vii° = B diminished (rare)

## Common progressions

### I-V-vi-IV (the "magic" progression)
Used in countless pop hits.
Examples: "Let It Be", "Don't Stop Believin'", "With or Without You"

### vi-IV-I-V
Same chords, reordered. Sadder opening.

### I-IV-V (blues, rock)
Three-chord foundation.

### ii-V-I (jazz)
Walking through key.

### Andalusian (i-VII-VI-V in minor)
Spanish/Middle Eastern feel.

## Key choice = mood

| Key | Common mood |
|-----|-------------|
| C major | Pure, simple, happy |
| G major | Open, hopeful |
| D major | Triumphant, bright |
| A major | Joyful, energetic |
| F major | Pastoral, calm |
| Bb major | Warm, romantic |
| C minor | Tragic, dark |
| A minor | Melancholic, contemplative |
| E minor | Sad, longing |
| F minor | Deeply sad, mournful |
| D minor | Serious, tragic |

(See key-signature-mood.md for full guide.)

## Chord substitutions (advanced)

### Borrowed chords
Borrow from parallel mode. C major borrowing iv (Fm) for color.

### Secondary dominants
Use V/V (D major in C key) to set up V (G).

### Chromatic mediants
Unrelated keys juxtaposed for surprise.

## For AI music (Suno)

Specify chord progression in prompt if you want specific:
```
[Style: indie folk, key F minor, chord progression Fm-Db-Ab-Eb]
```

Or just specify mood + genre and Suno picks appropriate harmony:
```
[Style: melancholic indie folk, F minor]
```

## Common harmony mistakes

- Always same progression
- Wrong key for vocal range
- No progression (just one chord)
- Too complex (overwhelming for genre)
- Bridge same chords as verse (no contrast)
