A chord progression or harmonic progression is a series of musical chords, or chord changes that "aims for a definite goal" of establishing (or contradicting) a tonality founded on a key, root or tonic chord[1] and that is based upon a succession of root relationships.[2] Chords and chord theory are generally known as harmony.
A chord progression can be thought of as a harmonic simultaneity succession: it offers an ongoing shift of level that is essential to many musical traditions. A change of chord, or "chord change", generally occurs on an accented beat, so that chord progressions may contribute significantly to the rhythm, meter and musical form of a piece, delineating bars, phrases and sections.[3] This is known as harmonic rhythm.
Contents [hide]
1 Basics
2 Simple progressions
3 Three-chord progressions
4 Blues changes
5 50s progression
6 Circle progressions
7 Harmonizing the scale
8 Minor and modal progressions
9 Chord progressions in classical music
10 See also
11 Sources
12 Further reading
13 External links
Basics[edit]
The key note or tonic of a piece of music is called note number one, the first step of the ascending scale. Chords built on each scale degree are numbered in the same way so that, for example, in the key of C, the progression E minor - F - G can be generally described as a three - four - five progression.
A chord may be built upon any note of a musical scale, therefore a seven-note scale allows seven basic chords, each degree of the scale becoming the root of its own chord.[4] A chord built upon the note A is an A chord of some type (major/minor/diminished, etc.) The harmonic function of any particular chord depends on the context of the particular chord progression in which it is found.[1] (See Diatonic function)
The diatonic harmonization of any major scale results in three major triads. They are based on the first, fourth, and fifth scale degrees (the tonic, subdominant and dominant[5] – see three-chord song). These three triads include, and therefore can harmonize, every note of that scale.
The same scale also provides three relative minor chords, one related to each of the three major chords. These are based upon the sixth, second and third degrees of the major scale and stand in the same relationship to one another as do the three majors, so that they may be viewed as the first, fourth and fifth degrees of the relative minor key. Separate from these six common chords there is one degree of the scale, the seventh, that results in a diminished chord.[6]
In addition, extra notes may be added to any chord. If these notes are also selected from the original scale the harmony remains diatonic. If new chromatic intervals are introduced then a change of scale or modulation occurs, which may bring the sense of a change of tonal center. This in turn may lead to a resolution back to the original key, so that the entire sequence of chords helps create an extended musical form.
Although all this allows for a large number of possible progressions (depending upon the length of the progression), in practice, progressions are often limited to a few bars' length and certain progressions are favored above others: there is a certain amount of fashion in this and a chord progression may even define an entire genre.
In western classical notation, chords built on the scale are numbered with Roman numerals. A D chord will be figured I in the key of D, for example, but IV in the key of A. Minor chords are signified by lower case Roman, so that D minor in the key of C would be written ii. Other forms of chord notation have been devised, from figured bass to the chord chart. These usually allow or even require a certain amount of improvisation.
Simple progressions[edit]
Diatonic scales such as the major and minor scales lend themselves particularly well to the construction of common chords because they contain a large number of perfect fifths. Such scales predominate in those regions where harmony is an essential part of music, as, for example, in the common practice period of western classical music. In considering Arab and Indian music, where diatonic scales are used, there are also available a number of non-diatonic scales, the music has no chord changes, remaining always upon the key-chord, an attribute which has also been observed in hard rock, hip hop,[7] funk, disco,[8] jazz, etc.
Alternation between two chords may be thought of as the most basic chord progression. Many well-known pieces are built harmonically upon the mere repetition of two chords of the same scale.[1] For example, many of the more straightforward melodies in classical music consist entirely or mostly of alternation between the tonic (I) and the dominant (V, sometimes with an added seventh), as do folk songs such as "Polly Wolly Doodle"[citation needed] and popular songs such as "Achy Breaky Heart".[citation needed] The Isley Brothers' "Shout" uses I - vi throughout.[9]
Three-chord progressions[edit]
Beethoven imagined in the process of composing his Pastoral Symphony
Three-chord tunes, though, are more common, since a melody may then dwell on any note of the scale. They are often presented as successions of four chords, in order to produce a binary harmonic rhythm, but two of the four chords are then the same. Often the chords may be selected to fit a pre-conceived melody, but just as often it is the progression itself that gives rise to the melody.
I - IV - V - V.
I - I - IV - V.
I - IV - I - V. (Common in Elizabethan music (Scholes 1977), this also underpins the American college song "Goodnight Ladies",[citation needed] is the exclusive progression used in Kwela.[10]
I - IV - V - IV.
IV-V-I progression in C About this sound Play (help·info)
Similar progressions abound in African popular music. They may be varied by the addition of sevenths (or other scale degrees) to any chord or by substitution of the relative minor of the IV chord to give, for example, I - ii - V. This sequence, using the chord based on the second scale degree, is also used cadentially in a common chord progression of jazz harmony, the so-called ii-V-I turnaround, on which are based the more ornate Coltrane changes.
Such progressions provide the entire harmonic foundation of much African and American popular music, and they occur sectionally in many pieces of classical music (such as the opening bars of Beethoven's Pastoral Symphony[citation needed]). Any of these progressions may be transposed into any key so that, for instance, the progression I - IV - V in the key of A will be played A - D - E, while in the key of C the chords will be C - F - G.
Where such a simple sequence does not represent the entire harmonic structure of a piece, it may readily be extended for greater variety. Frequently an opening phrase of the type I - IV - V - V, which ends on an unresolved dominant, may be "answered" by a similar version that resolves back onto the home chord, giving a structure of double the length:
I - IV - V - V
I - IV - V - I
Additionally, such a passage may be alternated with a different progression to give a simple binary or ternary form such as that of the popular thirty-two-bar form (see musical form).
Blues changes[edit]
Blues progressions influenced a great deal of 20th century American popular music
The twelve bar blues and its many variants use an elongated, three-line form of the I - IV - V progression that has also generated countless hit records, including the most significant output of rock and rollers such as Chuck Berry and Little Richard. In its most elementary form (there are many variants) the chords progress as follows:
I - I - I - I
IV - IV - I - I
V - IV - I - I
ii-V-I turnaround in C About this sound Play (help·info)
Again, blues progressions have formed the entire harmonic basis of many recorded songs but may also be confined to a single section of a more elaborate form, as frequently with The Beatles in such songs as "You Can't Do That", "I Feel Fine", and "She's A Woman".[citation needed] They have also been subjected to densely chromatic elaboration, as in the Bird blues.
Steedman (1984) proposed that a set of recursive rewrite rules generate all well-formed transformations of jazz, both basic blues chord changes and slightly modified sequences (such as the "rhythm changes"). Important transformations include:
replacement of (or addition to) a chord with its dominant, subdominant or the tritone substitution.
use of chromatic passing chords.
extensively applying the ii-V-I turnaround.
chord alterations such as minor chords, diminished sevenths, etc.[11]
50s progression[edit]
Main article: 50s progression
The Mills Brothers' recording of "Till Then" looked forward both to the end of World War II and to the popular music of the 1950s. (Courtesy of the Fraser MacPherson estate c/o Guy MacPherson)
Another common way of extending the I - IV - V sequence is by adding the chord of the sixth scale degree, giving the sequence I - vi - IV - V or I - vi - ii - V, sometimes called the 50s progression.
50s progression in C, ending with C About this sound Play (help·info)
In fact this sequence had been in use from the earliest days of classical music (used often by Wolfgang Amadeus Mozart[citation needed]), but after generating popular hits such as Rodgers and Hart's "Blue Moon" (1934),[citation needed] Jerome Kern and Dorothy Fields' 1936 "The Way You Look Tonight",[citation needed] and Hoagy Carmichael's "Heart and Soul" (1938),[12] it became associated with the black American vocal groups of the 1940s, The Ink Spots and The Mills Brothers ("Till Then"),[citation needed] and thus later became the entire basis of the 1950s doo-wop genre, a typical example being The Monotones' "The Book of Love".[citation needed]
Taken up into the pop mainstream, for example with Felice and Boudleaux Bryant's "All I Have to Do Is Dream",[citation needed] a hit for The Everly Brothers, in the 1960s it continued to generate records as othe