Exploring the Modal Architecture of Miles Davis's So What

Few recordings carry the gravitational pull of So What from Kind of Blue. Since its release in 1959, the tune has become a kind of doorway into jazz for listeners who otherwise might never wander down a smoky side street of improvisation. When I drop the needle, or more honestly the cursor, on it again, I keep finding new corners inside what sounds at first like a very simple piece. That simplicity is the trick, and the harmonic structure is the engine driving it.

Davis and his Columbia producer George Avakian gave the band a deceptively plain assignment: play over a couple of modes rather than a chain of chord changes. Bill Evans, who contributed the famous piano hook, understood the chord symbols were almost an afterthought. The piece does not lean on the dense bebop roadmap that ruled the late 1950s, instead offering a pair of modal vamps, a steady bass anchor, and an invitation to wander.

For an Australian listener in 2024, the tune still feels surprisingly current. The sparse harmonic backdrop is the same trick that producers across hip hop, neo-soul, and electronic music reach for when they want an improvisation to feel unmoored in a good way. If you have ever heard a Sydney act like Hermitude lean on a single minor pad for an entire track, you are hearing the ghost of So What walk past the door.

Australian audiences also encounter modal playing in unexpected places. The Wangaratta Jazz and Blues Festival regularly showcases local players working in a post-Davis vocabulary, and Melbourne's Jazzlab in Brunswick has become a small laboratory for exactly this kind of modal experimentation. Even a casual weekend at the Melbourne International Jazz Festival will surface an Australian band mining the same harmonic territory Davis mapped out more than six decades ago.

The Two-Chord Foundation in D Dorian and E♭ Dorian

The first thing to notice is that So What does not actually have a lot of chords. The opening vamp is built on D minor 7, moves up a whole step to E♭ minor 7, and then returns to D minor 7. That is essentially the entire harmonic furniture for the first half of the tune. Each of those chords functions less like a traditional tonic-dominant progression and more like a doorway into a mode.

D minor 7 is the chord, but the mode that lives above it is D Dorian. The difference matters. Dorian keeps the natural sixth degree raised, which gives the line a warm, slightly bright flavour against the minor root. E♭ minor 7 does the same thing a whole step higher, pointing toward E♭ Dorian. The ear registers that brightness even if the brain does not label it.

This kind of writing was a quiet revolution. Bebop tunes of the late 1940s and 1950s typically threw two or three chord changes per bar at the soloist. So What throws maybe one change every eight bars. The reduced harmonic rhythm gives each note the soloist plays more room to breathe. In a sense, Davis asked the band to play with a longer, slower pulse underneath the surface.

The Pedal Tone Trick and Bass Movement

Underneath those two chords sits one of the most economical bass lines ever recorded. Paul Chambers plays a D for the entire opening section, including the bars when the chord above him shifts to E♭ minor 7. That sustained low D acts as a pedal tone, a kind of harmonic anchor that grounds the rest of the band while the upper voices float.

The effect is subtle but powerful. Listeners feel the change to E♭, but they also feel the home base holding firm. It is a gesture borrowed from classical music, where pedal tones have appeared in everything from Bach organ works to Wagner. Davis and his arranger Evans understood that the contrast between a moving top and a stationary bottom creates a sense of suspended time.

This is a tool modern writers and producers still reach for. When I was working out a song idea recently, I found myself thinking about balancing blog and work, and the parallel hit me: just as a writer needs a stable base of routine to support the moving top of creative work, So What uses the bass as a constant foundation for the changing chords above.

Bill Evans's Voicings and the Economy of Harmony

Evans's piano part is the second harmonic pillar. Rather than filling the air with busy comping, he plays a two-note figure that simply outlines the chord on the strong beats and leaves the rest open. The famous hook is essentially a perfect fourth, an open fifth, and a small lift back down. It is so economical that the listener barely registers it as a piano part at all.

That restraint is a teaching moment. Evans understood that a chord does not need to be stated in full to imply its quality. The fourth between the piano's top notes is enough to tell the ear the harmony is minor 7. Anything more would clutter the texture and steal oxygen from the soloists.

Australian pianists working in the jazz tradition often cite Evans as a quiet influence. The late Mike Nock, who came out of the Sydney scene before spending decades in New York, played in a similarly open-handed way. The current generation of Melbourne players, many of them gigging around the Paris Cat or the Ellington Jazz Club, has inherited that instinct for letting the silence do the work.

The Soloists' Playground Over Modes

Once the structure is set, the band is free. Cannonball Adderley, John Coltrane, and Bill Evans all take solos over the same set of modal vamps. The harmonic content of each solo is therefore not a chain of passing chords but a single tonal centre that the soloist can colour in any way they choose.

Coltrane's solo is the most celebrated example. He uses the Dorian mode as a kind of palette, starting on the root and then bending lines around the natural sixth, the minor third, and the major seventh. Because the mode allows those notes to ring without clashing, his phrases feel searching rather than tense. He is painting with a wider brush than a bebop soloist would have used.

This approach also explains why So What has aged so well. Modal improvisation rewards melody and tone over speed. A teenage saxophonist in Adelaide working through the tune today can sound just as legitimate as Coltrane did in 1959, because the structure is not trying to trip them up. The composition is generous.

Why So What Still Sounds Fresh Decades Later

Plenty of recordings from 1959 sound locked in amber. So What does not. Part of that freshness comes from the harmonic content, and part of it comes from the recording itself, which was made in just two sessions with a small group and almost no overdubs. The sound of the room, the air around the instruments, the slight imperfections, all of it survives.

A generation of producers from Pharrell to the late J Dilla has chased that same feeling: a track that sounds both tightly constructed and slightly roomy. The harmonic content of So What supports that aesthetic because modal vamps are essentially loops. A producer can repeat one for eight bars without the listener growing bored, because the mode itself offers enough internal movement to keep the ear engaged.

For an Australian listener, this also explains the tune's quiet presence in places you might not expect. The same principle shows up in the work of artists like Gotye, whose Somebody That I Used to Know leaned on a minimal harmonic loop, or in the meditative pieces by Gurrumul Yunupingu, where a single modal centre carries an entire song. Davis would, I suspect, have appreciated the company.

Listening Strategies for the Curious Australian Listener

If you want to hear the harmonic structure clearly, a few small changes to your listening habit can help. First, listen once all the way through, then again with your attention on the bass line only. Notice how Paul Chambers holds his D for what feels like an impossibly long time, and how the upper chords drift above him like weather.

Next, isolate the piano. Evans's two-note figure is the harmonic compass, and once you hear it as a compass you will notice it sitting in the background of every chorus. From there, follow a single soloist for an entire pass. Pick Coltrane, Adderley, or Evans himself, and try to count how many times the chord changes beneath them. The answer, surprisingly, is very few.

Finally, listen to the tune on decent speakers or headphones. The harmonic detail lives in the spaces between the notes, and a cheap laptop speaker will sand those spaces off. A pair of over-ear headphones on a quiet evening in Brisbane or Perth will reveal textures that a commuter train in Sydney will not.

Modal Harmony Beyond Davis

Once you have spent time with So What, it is hard not to hear its fingerprints everywhere. Herbie Hancock's Maiden Voyage uses a similar modal framework, as does John Coltrane's Impressions. Later, the harmonic idea migrated into the work of pop producers, ambient musicians, and even some metal guitarists who discovered that a single mode can support a long, exploratory solo.

The lesson is portable. Strip a song down to a single modal centre, give a soloist room, and trust the listener to fill in the rest. This is the same instinct I find myself reaching for when I write about songwriters outside jazz, which is why I keep pointing readers back to why I think Jason Isbell is the best songwriter of his generation: both writers, in very different idioms, know that restraint is a form of generosity.

If you take one practical idea away from this piece, let it be this. The next time you sit down to write a song, build a single modal vamp and live inside it for sixteen or thirty-two bars before reaching for a chord change. Borrow a page from Davis and Evans. Let the bass hold the floor, trust the silence, and let the music tell you where it wants to go.