The So What chord
In the tune So What (Miles Davis, album Kind of Blue, 1959) the pianist Bill Evans answers the bass phrase with two chords; the first, from the bottom, is E – A – D – G – B: three stacked perfect fourths plus a major third on top. The second is the same structure a whole step lower: D – G – C – F – A. This structure (P4 – P4 – P4 – M3) is called the So What chord.
The form of the tune
AABA, 32 bars: 16 bars of D Dorian, 8 of Eb Dorian (bridge), 8 of D Dorian. It is the model of modal jazz; Impressions by John Coltrane (1961) uses the same form and the same centers.
Diatonic positions in D Dorian
The So What structure stays entirely within D Dorian (D E F G A B C) starting from three notes:
| Lowest note | Voicing | Reading over Dm |
|---|---|---|
| D | D G C F A | Dm11 (R, 11, b7, b3, 5) |
| E | E A D G B | Dm13 with the ninth as the lowest note (9, 5, R, 11, 13) |
| A | A D G C E | Dm7(11) with 9 on top (5, R, 11, b7, 9) |
Starting from other notes the structure leaves the mode (from F you would need Eb, from G you would need Bb), so in a Dorian vamp these three positions are alternated with “pure” fourth voicings.
Diatonic fourth voicings (3 notes) in D Dorian
| Voicing | Intervals | Note |
|---|---|---|
| D G C | P4 + P4 | stable |
| E A D | P4 + P4 | stable |
| F B E | A4 + P4 | contains the tritone: more tense |
| G C F | P4 + P4 | stable |
| A D G | P4 + P4 | stable |
| B E A | P4 + P4 | Dorian color (B = 6th) |
| C F B | P4 + A4 | tritone on top |
Moving these voicings by scale degree over a fixed bass on D is the sound of McCoy Tyner’s modal comping with Coltrane: the left hand often plays fifths or fourths (D – A – D), the right hand fourths moving in diatonic parallel.
Why fourths work in modal music
- Fourths do not clearly define a major or minor chord: they leave the tonal center to the bass and the mode.
- They give an open, modern sound, without the “sweetness” of thirds.
- They can be moved in parallel (planing) without creating functional progressions.
Beyond So What
- Fourth voicings over suspended dominants: over G7sus4 (G Mixolydian), D – G – C – F (5, R, 11, b7) and A – D – G – C (9, 5, R, 11) work; be careful not to use Bb, which does not belong to the mode.
- Upper structure in fourths over a chord: over Cmaj7#11, the fourths F# – B – E (#11, 7, 3) sound Lydian and bright.
- Fourths with the fifth in the bass: “quintal” voicing (C – G – D – A) for pads, widely used in post-rock and film music.
Listening examples
- Miles Davis, So What (1959), with Bill Evans on piano.
- John Coltrane, Impressions and A Love Supreme (1964), with McCoy Tyner.
- Herbie Hancock, Maiden Voyage (1965): sus and quartal chords.
Producer exercise
- Bass D (double bass or synth bass) held for 8 bars, 130 BPM swing.
- Piano: alternate the voicings E A D G B and D G C F A with the “So-what” rhythm (two chords, the second shorter).
- Then improvise by moving the 3-note voicings from the table (D G C → E A D → G C F…), always over the D.
- Move everything a half step up (Eb Dorian) for 8 bars: you have rebuilt the form of So What.
Related topics
Quartal and quintal harmony (basic lesson), Dorian vamp, sus chords and polymodality, planing and constant structures, Hindemith’s harmony.