The "So What chord" is a distinctive jazz piano voicing, closely associated with the iconic 1959 Miles Davis album Kind of Blue, particularly the opening track "So What." While the exact voicings used by pianist Bill Evans on the recording are complex and varied, the term "So What chord" has come to represent a specific type of quartal harmony—a chord built primarily from stacked perfect fourths—that evokes the open, modal, and ethereal sound characteristic of the piece.
Musical Characteristics
- Quartal Harmony: The most defining characteristic is its construction using perfect fourths rather than the traditional perfect thirds (tertian harmony) that form most Western classical and jazz chords. This creates a less tonally rooted, more ambiguous, and "open" sound.
- Structure: While variations exist, a common pedagogical representation of the "So What chord" for a minor chord (e.g., D minor) is a stack of four perfect fourths followed by a major third at the top. For a D minor context, this often manifests as:
- A-D-G-C-E (from bottom to top).
- Analyzing the intervals: A to D is a perfect fourth (P4), D to G is a P4, G to C is a P4, and C to E is a major third (M3).
- Sound: The chord produces a cool, spacious, and often reflective quality. It avoids the strong tension-and-resolution feel of functional harmony, contributing to the "floating" nature of modal jazz. It is typically interpreted as a minor 7th chord with added extensions, such as a 9th and/or 11th (e.g., Dm11 or Dm9sus4).
- Absence of Third (often): In some pure quartal voicings, the traditional major or minor third of the chord might be deliberately omitted or placed very high, further contributing to its ambiguity and modal character. In the A-D-G-C-E example, the F (the minor third of Dm7) is absent, replaced by the G (11th) and E (9th), which outlines a D minor sound through context.
Origin and Context
The "So What chord" derives its name directly from Miles Davis's 1959 composition "So What," which is the first track on the seminal modal jazz album Kind of Blue. The piece is predominantly built on just two chords: a D minor 7th for the A sections and an Eb minor 7th for the B section.
Pianist Bill Evans, known for his innovative harmonic language and voicings, played a crucial role in shaping the sound of Kind of Blue. His piano voicings on "So What" were groundbreaking, making extensive use of spread voicings, extensions (9ths, 11ths), and open harmonies that often emphasized intervals other than thirds, including fourths and seconds. While the specific A-D-G-C-E stack might be a simplification or generalization of Evans's actual playing on the track, it encapsulates the essence of the harmonic language he introduced, which heavily influenced subsequent jazz pianists and composers.
Musical Significance and Usage
The "So What chord" represents a pivotal moment in jazz harmony:
- Departure from Tertian Harmony: It signaled a significant shift away from the strict tertian harmony that had dominated jazz up to that point. By prioritizing stacked fourths, it opened new avenues for harmonic expression.
- Influence on Modal Jazz: It became a hallmark of modal jazz, where chords function more as colors or soundscapes than as components of a rigid functional progression. The open sound of these voicings perfectly complemented the extended improvisations over static modes.
- Impact on Jazz Piano: The voicings pioneered by Bill Evans on Kind of Blue had a profound and lasting impact on jazz piano technique and pedagogy. Learning "So What" voicings became a standard part of jazz education.
- Contemporary Applications: Beyond modal jazz, the "So What chord" and similar quartal voicings are widely used in contemporary jazz, film scoring, and other genres where a sophisticated, open, or ethereal harmonic quality is desired.
In essence, the "So What chord" is more than just a collection of notes; it represents a philosophy of harmony that embraces openness, ambiguity, and a departure from traditional functional relationships, forever changing the landscape of jazz.