History and Development of Jazz Harmony: Armstrong to Parker

Louis Armstrong and the Foundations of Jazz Harmony

Unlike much of the jazz that was to follow in later eras, which placed a heavy emphasis on the use of $ii-V-I$ progressions, the music of Louis Armstrong focused primarily on primary triads. These are the chords built on the first, fourth, and fifth degrees of the scale, denoted as $I$, $IV$, and $V$. Armstrong frequently enhanced these basic triads with the addition of $7th$ intervals. To provide further chromatic interest and harmonic movement, he utilized secondary dominants and diminished chords. This harmonic approach preserves a strong link to traditional blues progressions, which rely heavily on primary triads and dominant $7th$ chords. Additionally, the inclusion of secondary dominants and diminished chords can be viewed as an element borrowed from Romantic era harmony, creating an inventive blend of styles.

Harmonic Analysis of "Hotter Than That"

An example of Armstrong's sophisticated use of primary chords, secondary dominants, and diminished chords is found in "Hotter Than That". The piece opens with an 8-bar introduction featuring typical New Orleans polyphony, which serves as a turnaround to establish the home key of $F$ major. The main structure begins with four bars of the tonic $F$ chord. In the subsequent bars, a $7th$ is added to the tonic, creating a secondary dominant ($F7$) that resolves to three bars of the subdominant chord, $Bb$. To link back to the tonic, a chromatic diminished $7th$ chord on $B$ ($B^{\circ}7$) is employed before returning to the tonic over a dominant pedal ($F/C$). This is followed by a chain of secondary dominants—$D7$, $G7$, and $C7$—which lead back to the tonic $F$. The full chord sequence for this section is represented as:

$|F |F|F|F |F7|F7|Bb|Bb|Bb|B^{\circ}7|F/C|D7|G7|C7|F |F ||$

Advanced Chromaticism in "West End Blues"

While Louis Armstrong often utilized simpler harmonic structures, he would occasionally deviate into more complex territory by including chromatic alterations to the primary triads, most frequently targeting the $V$ chord. A prominent instance of this occurs near the beginning of "West End Blues". Following a monophonic improvised trumpet solo, the entire ensemble plays a sustained dominant $7\#5$ chord ($Bb7\#5$) before the restatement of the head melody. This inclusion of a dominant $7\#5$ chord signals the harmonic complexity that would eventually become a standard hallmark of the jazz styles that followed Armstrong.

Despite this advanced chromatic moment, what follows is a traditional 12-bar blues progression in the key of $Eb$, performed in a typical Dixieland style. In this arrangement, the trumpet states the head melody, the clarinet provides the harmonisation, and the trombone outlines the harmony. The rhythm and foundation are provided by the accompaniment of the tuba and banjo. The progression follows this pattern:

$Eb \, Eb \, Eb \, Eb7$

$Ab7 \, Ab7 \, Eb \, Eb$

$Bb7 \, Bb7 \, Eb \, Bb7$

Charlie Parker and the Bebop Evolution

Charlie Parker was a central figure in the development of bebop harmony. He was known less for composing entirely original material from scratch and more for his adaptation of existing songs. This process, known as contrafact, involves taking the chord progressions of well-known songs and applying new melodies to them. Parker frequently adapted the standard 12-bar blues progression, transforming it through the use of elaborate chord substitutions and adaptations. While some might argue that a reliance on existing structures suggests a lack of creativity, bebop artists used these substitutions to transform familiar progressions into vibrant, complex, and creative new musical landscapes.

Harmonic Substitution in "Blues for Alice"

"Blues for Alice" serves as a notable example of the elaborate substitutions used in bebop. Written in the key of $F$ major, the piece begins with a piano introduction accompanied by drums. This is followed by the alto saxophone (Parker) and a flute playing the head melody in unison, supported by a traditional bebop rhythm section (piano, bass, and drums). While a traditional 12-bar blues might stay on the tonic for several bars, "Blues for Alice" immediately moves through a circle of 5ths progression in bars 2 through 4, incorporating several secondary dominants.

In bar 5, the harmony reaches the expected subdominant chord ($IV7$ - $Bb7$), but immediately shifts into a series of chromatically descending $ii^7-V$ changes in bars 6 to 8. These changes suggest different keys without actually resolving to a tonic harmony. In bars 9 and 10, a standard jazz replacement for the traditional $V-IV$ blues sequence is used in the form of a $ii^7-V$ progression in the home key ($Gm7$ to $C7$). However, resolution is delayed as Parker sidesteps the tonic, moving to the mediant ($iii^7$ - $Am7$). This initiates a circle of 5ths-based turnaround ($iii-vi-ii-V$) involving the chords $Am7$, $Dm7$, $Gm7$, and $C7$, which finally leads back to the tonic for the start of the next chorus, which is an improvised alto sax solo. The detailed sequence is:

$F6 \, E\phi7 \, A7b9 \, Dm7 \, G7 \, Cm7 \, F7$

$Bb7 \, Bbm7 \, Eb7 \, Am7 \, D7 \, Abm7 \, Db7$

$Gm7 \, C7 \, Am7 \, Dm7 \, Gm7 \, C7$

Traditionalism and Blues Influence in "Parker's Mood"

While bebop is often associated with frequent substitutions and break-neck speeds, Parker also maintained a deep connection to the traditional blues. "Parker's Mood" is a representation of a fairly traditional 12-bar blues in the key of $Bb$ major. Following a saxophone flourish and a brief, harmonically adventurous rhythm section introduction, the main progression is established. The chords for this 12-bar structure are:

$| Bb | Eb9 | Bb7 | Bb7 | Eb7 | Eb7 | Bb7 | Dm7, G7b9 | Cm7 | F7 | Bb7, Cm7 | F7 |$

Apart from the "back-door" $ii-V$ progression in bar 8 that leads into the $Cm7$ of bar 9, the chords are largely traditional. Parker’s head melody is improvisatory and virtuosic, yet it emphasizes the flattened $3rd$ ($Db$) in bars 5 and 6 and the flattened $7th$ ($Ab$) in bars 4, 6, and 11. These notes are characteristic of the traditional blues scale. The tempo of this piece is laid-back and bluesy, contrasting with fast-tempo tunes like "Anthropology". Although the final saxophone solo briefly moves into double-time, the tune returns to its contemplative, laid-back feel by the piano-dominated outro, highlighting the blues-inspired side of Parker's bebop style.