Jazz progression


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Jazz progression
Figure: jazz progression

jazz progression plays jazz progressions by a clarinet choir comprising two soprano clarinets, one alto clarinet and a bass clarinet. The jazz progression figure shows the score

A jazz progression is a chord progression that is commonly used in jazz harmony.

Turnaround is another name for a jazz progression, especially chord changes at the end of a section, equivalent to a cadence in functional harmony.

A jazz progression can start on the tonic I, end on the tonic I or the dominant seventh V, and repeat this cycle indefinitely with variations. The chords are mainly seventh chords and voiced complete or incomplete. The root commonly progresses by fifth down, but can repeat or move by step or third up or down.

ii-V-I is the default jazz progression. The root progresses by fifth down from ii to V, then by fifth down again in the familiar V to I. Using seventh chords, the progression becomes ii7-V7-Imaj7 in a major key. The second bar of jazz progression starts with this progression. There are loads of variations. vi-ii-V-I consists of three consecutive root movements by fifth down and a shortened version, vi-ii-V, is shown in the first bar. Another popular variant is I-vi-ii-V.

Minor key jazz progressions also use root movement down by fifth. ii7b5-V7-iminmaj7 is the minor key equivalent of the major ii7-V7-Imaj7. It contains a half-diminished seventh followed by a dominant seventh followed by a minor major seventh. The iminmaj7 chord can be replaced by i7 from the jazz minor scale to produce ii7b5-V7-i7.

Autumn Leaves, written in 1945 by Joseph Kosma, is a popular jazz standard and a good example of a jazz progression through relative keys using the diatonic circle of fifths. In the key of C major a progression down by a fifth, starting on D, produces the root motion D-G-C-F-B-E-A. The first half of Autumn Leaves is in the key of C and progresses Dmaj7-G7-Cmaj7-Fmaj7, iimaj7-V7-Imaj7-IVmaj7. It contains the ubiquitous ii-V-I progression. Now the clever bit. The second half of the progression modulates to the relative minor key, A minor, and progresses Bm7b5-E7-Am7, ii7b5-V7-i7. This progression is reproduced in bar 3 of jazz progression.

The ii-V-I progression can easily be extended through modulation by converting the tonic I chord in the old key into a supertonic minor ii chord in the new key. To modulate from C major to Bb major, for example, use Cmaj7-Dm7-G7-Cmaj7, I-ii-V-I, in C major, followed by Cm7-Fmaj7-Bbmaj7-Bmaj7, ii-V-I-I in Bb major. The chord change from Cmaj7 to the parallel key of Cm7 is the modulation.

Rhythm changes is the name given to another popular type of jazz progression. It actually consists of two jazz progressions: first is I-vi-ii-V, a variant on the usual ii-V-I; second is I-I-IV-iv-I-V-I-I, which mixes the familiar I, IV, and V chords found in functional and pop harmony with the less familiar IV-iv-I progression. The name, rhythm changes, is derived from the song I Got Rhythm written by George Gershwin.

The root of a jazz progression can move by third. Two notes a third apart are separated by four consecutive fifths and root progression by thirds is a form of distant key modulation. For example, the keys E and Ab are respectively a third above and below the key of C. Modulation through these keys is achieved using a series of ii-V-I-I progressions. For example, Dm7-G7-Cmaj7, ii-V-I in C, followed by F#m7-B7-Emaj7, ii-V-I in E, followed by Bbm7-Eb7-Abmaj7, ii-V-I-I in Ab, followed by a return to C.

Coltrane changes are a good example of root movement by third, in this instance, by major third. A Coltrane change by major third up is shown in bar 4 of jazz progression. The root notes, Ab-C-E, form an augmented triad. The progression is named after the influential jazz writer and performer John Coltrane.

jazz progression illustrates the differences between jazz harmony and functional harmony. Jazz theory is a little fuzzy about this relationship. Sometimes it uses the terminology of functional harmony and talks about chord function, chord resolution and voice leading. This gives the impression that jazz harmony is an extension of functional harmony, and follows similar rules, except that it uses a seventh chord rather than a triad. At other times jazz appears to be separate to, and distinct from, functional harmony. The guide firmly believes that jazz harmony is fundamentally different to functional harmony for three reasons: chord resolution is impossible in a system of harmony based on the seventh chord; voice leading is weak in jazz harmony; and a jazz chord is probably nonfunctional. Let us examine each of these in turn.

The difference between jazz and functional harmony is best illustrated by chord resolution, the motion from dissonance to consonance. A seventh chord, the basis of jazz harmony, is a dissonant chord, because it contains at least one dissonant interval. In functional harmony, a dissonance always resolves to a consonance. Therefore, a seventh chord should always resolve to a consonant chord. However, there are only two consonant chords, the major and the minor triads. All other chords are dissonant: the diminished triad, augmented triad, suspended chord, add chord and seventh chord are all dissonant. A system of harmony based on any of these chords cannot coexist with the concept of resolution, something has to give. Since two consecutive seventh chords can, and regularly do, follow each other in jazz harmony, there is no resolution. Jazz harmony thus embraces dissonance.

Voice leading is weak in jazz harmony, so weak that the rules are really only suggestions which can be summed up thus: put a common note in the same part, otherwise move by step, otherwise move by leap; put the melody in the top soprano part; and move the bass and soprano parts in contrary motion. jazz progression follows these suggestions.

One of the main purposes of voice leading in functional harmony is to avoid parallel fifths and octaves. Jazz harmony raises an additional consideration, how to voice lead parallel sevenths and seconds. Functional harmony has definite views on parallel fifths and octaves but is silent on parallel sevenths and seconds. It is not addressed simply because parallel sevenths and seconds do not and cannot occur in functional harmony, a seventh chord must always resolve to a triad. For voice leading to be meaningful in jazz harmony it must include all parallel motion, sevenths and seconds as well as fifths and fourths, and thirds and sixths. No such theory exists.

Finally, jazz chords are probably nonfunctional. The purpose of a jazz chord is largely to sound good, rather than to promote tonality. Whilst a lot of jazz is definitely tonal and has a clear key, a lot is not. Some approaches to jazz harmony, such as modal jazz, for example, are aimed at weakening, not strengthening, the idea of key.

In summary, the guide treats a jazz chord as largely nonfunctional, tries to avoid mentioning chord resolution altogether, pretty much ignores voice leading, and promotes any type of parallel motion. Not too radical, one hopes.