VI. Jazz
Blues Harmony
Bryn Hughes and Megan Lavengood
Key Takeaways
- 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.
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 :
- 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.
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 . “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.
Voice leading
Because the root motion in a 12-bar blues is all by fifth and by step, voice leading in the harmonies can be very smooth. Commonly, instruments playing harmony in a blues song will connect the chordal thirds and sevenths to create smooth voice leading, as in Example 2. (Voicing is discussed more in another chapter.)
More Blues Schemas
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 ( ). “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 ( ).
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
.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.
One recording that performs the blues this way is the Lincoln Center Jazz Orchestra performing Duke Ellington’s “C Jam Blues.” This is easiest to hear during the solo sections; however, not every repetition of this blues contains every chord shown in .
Examples of Variations
The blues can be varied extensively yet still qualify as the blues. This chapter’s Spotify playlist goes through several tracks that have some slight variations on the schemas outlined above:
- “Runaway Blues” by Ma Rainey (1928) uses a IV in the first tonic phrase, and it also embellishes the final V with an applied V/V.
- “Empty Bed Blues, Pt. 1” by Bessie Smith (1928) follows a basic 12-bar blues but precedes most new harmonies with a tonicizing ii–V progression.
- “Surfin’ USA” by the Beach Boys (1963) presents a 16-bar blues, but the first two phrases each begin with two bars of V before two bars of I.
- “The Thrill is Gone” as recorded by B.B. King (1970) is in minor, and it replaces the ii–V of the final phrase with ♭VI–V.
Musicians who have developed a familiarity with the blues will have no trouble recognizing the blues in a tune even with these variations and more.
- Worksheet on 12-bar blues (.pdf, .mscz). Asks students to write basic and jazz 12-bar blues progressions, voiced and unvoiced, and to analyze altered blues progressions. Worksheet playlist
- Worksheet on 12-bar blues, no jazz (.pdf, .mscz). Same as Assignment 1, but simplified: aks students to write basic 12-bar blues progressions, voiced and unvoiced, and to identify unusual chords in altered blues progressions. Worksheet playlist
Media Attributions
- 16-bar blues © Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
A seventh chord in which the triad quality is major and the seventh quality is minor.
A prototypical chord progression or formal structure.
A variation on the 12-bar blues progression. Typically composed of four four-bar phrases, usually two iterations of tonic, followed by subdominant and dominant. The final phrase may or may not end with a turnaround.
The minor blues differs from the standard 12-bar blues by having minor seventh chords on the i and iv chords, and replacing the V–IV–I cadence with a ii–V–I cadence.
The jazz blues incorporates several alterations to the 12-bar blues to blend together blues harmony and jazz harmony. In the eighth bar, instead of remaining on tonic, there is an applied ii–V that leads to the ii chord in bar 9. In the third phrase, the V–IV–I of the standard blues is replaced with a ii–V–I more common to jazz.
A tone that exists outside of the twelve-tone equal-tempered scale (for example, quarter tones).
The role that a musical element plays in the creation of a larger musical unit.
A plagal cadence uses the harmonies IV–I.
A cadence with the harmonies V–I. The harmonies are typically in root position. Authentic cadences can be further distinguished by their melody note in the I chord: an authentic cadence ending on 1̂ in the melody is a perfect authentic cadence, while one with 3̂ or 5̂ in the melody is an imperfect authentic cadence.
A type of jazz/pop score that typically notates only the melody and the chord symbols (written above the staff).
Typically comprises three phrases of four bars each. 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). The third phrase may or may not end with a turnaround.
The use of a non-tonic chord (usually dominant) at the end of a harmonically closed unit to transition into the beginning of the following on-tonic unit. In jazz, the term "turnaround" often refers to the progression vi–ii–V–I. The exact qualities of these chords are highly variable, and one or more of the chords may be substituted with a different, related chord.
The distance between roots of adjacent chords. For example, "root motion by step" refers to the distance between two chords that are only one step apart, such as I and ii, IV and V, etc. Note that the root is not always in the bass, so this is a separate concept from bass motion.
The way a specific voice within a larger texture moves when the harmonies change. For example, in a choir with four parts, soprano/alto/tenor/bass, one might discuss the voice leading in the tenor part as the entire choir moves from I to V.
A mode with a range of a fifth above and fourth below its tonic.
In church modes, authentic modes are those that range from final to final.