Triad plus a seventh: major7, dominant7, minor7, half-diminished, fully diminished.
Seventh Chord
A Seventh Chord expands the triad by adding another third on top, producing a four-note structure that introduces new shades of tension and color.
While triads define basic tonality, seventh chords establish function, direction, and complexity—they are the backbone of jazz, pop, blues, and classical harmony alike.
Structure
A seventh chord contains:
1. Root – establishes the chord’s name and tonal center
2. Third – defines major or minor quality
3. Fifth – stabilizes the chord (perfect, diminished, or augmented)
4. Seventh – adds depth and harmonic tension, determining the chord’s pull toward resolution
Stacked thirds example (C-based):
| Chord | Notes | Intervals above Root (in semitones) | Character |
|---|---|---|---|
| Cmaj7 | C E G B | 0 – 4 – 7 – 11 | Smooth, resolved |
| C7 | C E G B♭ | 0 – 4 – 7 – 10 | Strong, dominant tension |
| Cm7 | C E♭ G B♭ | 0 – 3 – 7 – 10 | Warm, mellow minor |
| Cdim7 | C E♭ G♭ A | 0 – 3 – 6 – 9 | Symmetrical, very tense |
| Cm7♭5 | C E♭ G♭ B♭ | 0 – 3 – 6 – 10 | Half-diminished, jazz minor color |
Interval Stacking Logic
Each type of seventh chord is created by altering one or more of the upper intervals:
- Major triad + major 7th → Major Seventh
- Major triad + minor 7th → Dominant Seventh
- Minor triad + minor 7th → Minor Seventh
- Diminished triad + minor 7th → Half-diminished (m7♭5)
- Diminished triad + diminished 7th → Fully diminished (dim7)
This extra third (the 7th) adds a voice-leading function—it almost always wants to resolve by step, giving motion to harmonic progressions.
Inversions
Seventh chords have four positions depending on which chord tone is in the bass:
| Inversion | Bass Note | Example (C7) | Symbol | Use |
|---|---|---|---|---|
| Root Position | Root (C) | C–E–G–B♭ | C7 | Full strength, dominant function |
| 1st Inversion | 3rd (E) | E–G–B♭–C | C7/E | Smooth internal voice movement |
| 2nd Inversion | 5th (G) | G–B♭–C–E | C7/G | Passing motion, softens weight |
| 3rd Inversion | 7th (B♭) | B♭–C–E–G | C7/B♭ | Strong pull downward by 7th |
Harmonic Function
| Chord Type | Function | Feels Like | Typical Resolution |
|---|---|---|---|
| Major Seventh | Tonic or subdominant | Relaxed, complete | May stay static |
| Dominant Seventh | Dominant | Urgent, unstable | Resolves down a 5th or up a 4th |
| Minor Seventh | Tonic or subdominant (minor) | Smooth, soulful | Often to ii–V–I or i–iv |
| Half-diminished | Pre-dominant in minor keys | Tense, expectant | Moves to V or V7 |
| Diminished Seventh | Intensely unstable | Dramatic | Resolves by semitone to tonic |
Usage and Style
- Classical: introduces controlled dissonance leading to cadence resolution
- Jazz: essential color chords for ii–V–I movement
- Pop/Rock: adds warmth, soul, and sophistication to simple progressions
- Blues: the dominant seventh defines its harmonic identity
Examples
| Song | Artist | Chord Use |
|---|---|---|
| “Something” | The Beatles | Cmaj7 adds lush resolution |
| “Stormy Weather” | Harold Arlen | Dominant 7ths drive the blues flow |
| “Autumn Leaves” | Jazz Standard | ii–V–I built entirely on 7ths |
| “Creep” | Radiohead | Gmaj7 for melancholic tension |
| “Georgia on My Mind” | Ray Charles | Mix of maj7 and dom7 color chords |
Summary
| Attribute | Value |
|---|---|
| Formula | 1 – 3 – 5 – 7 |
| Core Function | Adds color, tension, and direction to triads |
| Tonal Colors | Major, Minor, Dominant, Diminished, Half-diminished |
| Inversions | Four (root through 7th in bass) |
| Use | Core of tonal and modal harmony, essential in jazz and blues |