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VI. Jazz
Blues Harmony

### Core Idea

Blues harmony differs from tonal and jazz harmony in a number of important ways, especially in the treatment of the dominant seventh chord. In a standard 12-bar blues, all chords are dominant seventh chords.

### Explanation

Blues harmony differs from tonal and jazz harmony in a number of important ways, especially in the treatment of the dominant seventh chord.

In a standard 12-bar blues, all chords are dominant seventh chords.

The blues is a schema that can have many alterations without ceasing to qualify as "a blues."

Common variations on the 12-bar blues are the 16-bar blues, the minor blues, and the jazz blues.

The jazz blues blends jazz and blues harmonic languages together.

Chapter playlist

The blues is an extraordinarily important genre in U.S. popular music. Not only is the tradition itself very old, with roots reaching back to the music of enslaved African Americans, but it continues to exert influence on 21st-century popular music.

The documentation on the history of the blues is quite limited due to its age, but the earliest blues songs existed in the late 1800s, and it seems to have grown out from earlier African American musical styles, such as field hollers and work songs, as well as microtonal and rhythmic characteristics of West African music. In this sense, although jazz musicians very frequently play the blues, the blues as a tradition has distinct origins from jazz. Jazz developed first in New Orleans through a mix of African, Caribbean, and European influences. The result of this distinction is that many of the truisms of jazz or tonal music do not hold true in the blues. Among the biggest harmonic differences are:

Dominant-quality seventh chords can have any function (tonic, dominant, or subdominant).

Plagal cadences provide structural closure, instead of authentic cadences.

Major and minor thirds are freely mixed together, and even used simultaneously (sometimes written in chord symbols as a major/dominant chord with a ♯9 extension).

This chapter introduces some of the most common forms of the blues encountered in the 20th and 21st centuries.

12-Bar Blues

The blues is a schema: a frame of reference for understanding lots of different chord progressions. Blues progressions can all be understood as outgrowths from a basic prototype.

The 12-bar blues progression is composed of three phrases, typically four bars each. A major difference between the blues and more traditionally tonal music is that it emphasizes plagal cadences instead of authentic cadences. At its most basic, the harmony progresses as shown in Example 1:

The first phrase is entirely tonic harmony (I).

The second phrase contains two bars of subdominant (IV) and two bars of tonic (I).

The final phrase begins with one bar of dominant (V) followed by one bar of subdominant (IV) and two bars of tonic (I).

All chords are dominant seventh chords and do not fit into a single key.

Example 1. A basic 12-bar blues.

This is the simplest version of the 12-bar blues, but innumerable variations exist upon these changes. One of the most common additions is that the second bar may move to IV, then return to I in the third bar. Another especially common trick is to employ some type of turnaround in the final bar or two of the progression, from something as simple as a V7 chord to a full III–VI–II–V progression. It can be difficult to find a blues tune that doesn't make some alteration from the basic form shown in Example 1. "You Can't Do That" by the Beatles (1964) is nearly the same, but it does add a V chord in the final bar as a turnaround.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2019/08/16-bar-blues.png) Example 2. 16-bar blues.

Closely related is the 16-bar blues progression, which is composed of four 4-bar phrases, usually two iterations of tonic followed by subdominant and dominant (Example 2). "Hoochie Coochie Man" by Muddy Waters (1954) is one example of a 16-bar blues. Notice that the final phrase may or may not end with a turnaround. The 16-bar blues is not as common as the 12-bar blues, but it has somewhat heightened frequency in blues-based rock music.

Most commonly, the blues is in "major" (which, in this context, simply means that the tonic harmony has a major third above it—many pitches in a major blues fall outside the major scale). But another common variation on the blues is a minor blues. In a minor blues, the i and iv chords are minor sevenths instead of dominant sevenths; the V stays dominant. Because the motion from the major V to the minor iv can sound anticlimactic, the minor blues also typically replaces the V–IV–I motion in the third phrase with a ii–V–I (Example 3).

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Example 3. A typical minor blues.

Jazz Blues

As mentioned in the introduction to this chapter, the blues treats harmony differently from jazz, and one of the large differences is the reliance upon plagal rather than authentic cadences. The jazz blues is a variant of the 12-bar blues that mitigates this somewhat by adding several ii–V progressions to the blues.

Like the 12-bar blues, the jazz blues is composed of three 4-bar phrases. A basic version of the jazz blues is presented in Example 4.

Notice that the jazz blues mixes typical blues harmony (i.e., the use of non-V dominant seventh chords and plagal resolutions) with jazz harmonic schemas: specifically, it uses ii–Vs and turnarounds. In bar 8, instead of remaining on tonic, there is an applied ii–V that leads to the ii chord in bar 9. And in the third phrase, the V–IV–I of the standard blues is replaced with a ii–V–I more common to jazz.

Example 4. The jazz blues adds ii–V progressions, replacing structural plagal cadences.

One recording that performs the blues this way is the [Lincoln Center Jazz Orchestra performing Duke Ellington's "C Jam Blues."](https://open.spotify.com/track/5egcvD0mnAU1hLQulxxPKI?si=NCkNwS

### Key Quote

In a standard 12-bar blues, all chords are dominant seventh chords.

### Application Scenarios

The 12-bar blues progression is composed of three phrases, typically four bars each. A major difference between the blues and more traditionally tonal music is that it emphasizes plagal cadences instead of authentic cadences. At its most basic, the harmony progresses as shown in Example 1:

Example 1. A basic 12-bar blues.

This is the simplest version of the 12-bar blues, but innumerable variations exist upon these changes. One of the most common additions is that the second bar may move to IV, then return to I in the third bar. Another especially common trick is to employ some type of turnaround in the final bar or two of the progression, from something as simple as a V7 chord to a full III–VI–II–V progression. It can be difficult to find a blues tune that doesn't make some alteration from the basic form shown in Example 1. ["You Can't Do That" by the Beatles](https://open.spotify.com/track/5b9G4dtK3Tdguuy9BO3Nwo?si=7GMoz0VBQQiY8wrqopy7jA) (1964) is nearly the same, but it does add a V chord in the final bar as a turnaround.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2019/08/16-bar-blues.png) Example 2. 16-bar blues.

### Key Terminology

12-bar blues progression dominant seventh chord chord symbols seventh chord minor blues subdominant jazz blues authentic function harmony schema phrase

### Related Links

Chapter playlist"You Can't Do That" by the Beatles https://viva.pressbooks.pub/app/uploads/sites/12/2019/08/16-bar-blues.png"Hoochie Coochie Man" by Muddy Waters ii–V progressions ii–Vs Lincoln Center Jazz Orchestra performing Duke Ellington's "C Jam Blues."This chapter's Spotify playlist applied V/V tonicizing ii–V
Source: https://viva.pressbooks.pub/openmusictheory/chapter/blues-harmony/
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