In music theory, chord substitution is the technique of using a chord in place of another in a progression of chords, or a chord progression. Much of the European classical repertoire and the vast majority of blues, jazz and rock music songs are based on chord progressions. "A chord substitution occurs when a chord is replaced by another that is made to function like the original. Usually substituted chords possess two pitches in common with the triad that they are replacing." [1]
A chord progression may be repeated to form a song or tune. Composers, songwriters and arrangers have developed a number of ways to add variety to a repeated chord progression. There are many ways to add variety to music, including changing the dynamics (loudness and softness).
In J. S. Bach's St Matthew Passion , the chorale "Herzliebster Jesu" makes its first appearance in a straightforward harmonisation:
Later, as the Passion Story draws towards its sombre conclusion, we find "a more chromatic and emotional setting of the melody" that passes through "no less than ten chords with grinding chromatic steps in the bass": [2]
The well-known theme of the second movement of Joseph Haydn's String Quartet, Op. 76 No. 3 is harmonized simply at the start:
Haydn later "reharmonizes the theme". [3] Hans Keller calls this "the fullest and richest statement" [4] of the famous melody: "In the second bar, for instance, there even is a turn to the relative minor": [5]
The diminished triad can be used to substitute for the dominant seventh chord. In major scales, a diminished triad occurs only on the seventh scale degree. For instance, in the key of C, this is a B diminished triad (B, D, F). Since the triad is built on the seventh scale degree, it is also called the leading-tone triad . This chord has a dominant function. Unlike the dominant triad or dominant seventh, the leading-tone triad functions as a prolongational chord rather than a structural chord since the strong root motion by fifth is absent. [7]
Jazz musicians often substitute chords in the original progression to create variety and add interest to a piece.
The substitute chord must have some harmonic quality and degree of function in common with the original chord, and often only differs by one or two notes. Scott DeVeaux describes a "penchant in modern jazz for harmonic substitution." [8]
One simple type of chord substitution is to replace a given chord with a chord that has the same function. Thus, in the simple chord progression I–ii–V–I, which in the key of C major would be the chords C Major–d minor–G Major–C Major, a musician could replace the I chords with "tonic substitutes". The most widely used substitutes are iii and vi (in a Major key), which in this case would be the chords "e minor" and "a minor".
This simple chord progression with tonic substitutes could become iii–ii–V–vi or, with chord names, "e minor–d minor–G Major–a minor". Given the overlap in notes between the original tonic chords and the chord substitutes (for example, C major is the notes "C, E, and G", and "e minor" is the notes "E, G and B"), the melody is likely to be supported by the new chords. The musician typically applies a sense of the musical style and harmonic suitability to determine if the chord substitution works with the melody.
There are also subdominant substitutes and dominant substitutes. For subdominant chords, in the key of C major, in the chord progression C major/F major/G7/C major (a simple I /IV/V7/I progression), the notes of the subdominant chord, F major, are "F, A, and C". As such, a performer or arranger who wished to add variety to the song could try using a chord substitution for a repetition of this progression. One simple chord substitute for IV is the "ii" chord, a minor chord built on the second scale degree. In the key of C major, the "ii" chord is "d minor", which is the notes "D, F, and A". As there are two shared notes between the IV and "ii" chords, a melody that works well over IV is likely to be supported by the "ii" chord.
The ii–V substitution is when a chord or each chord in a progression is preceded by its supertonic (ii7) and dominant (V7), or simply its dominant. [9] For example, a C major chord would be preceded by Dm7 and G7. Since secondary dominant chords are often inserted between the chords of a progression rather than replacing one, this may be considered as 'addition' rather than 'substitution'.
Chord quality alteration is when the quality of a chord is changed, and the new chord of similar root and construction, but with one pitch different, is substituted for the original chord, for example the minor sixth for the major seventh, or the major seventh for the minor. [10]
The diminished seventh chord is often used in place of a dominant 7th chord. In the key of A Major the V chord, E dominant 7th (which is made up the notes E, G♯, B, and D) can be replaced with a G♯ diminished seventh chord (G♯, B, D, F). If the diminished seventh chord (G♯) is followed by the I chord (A), this creates chromatic (stepwise semitonal) root movement, which can add musical interest in a song mainly constructed around the interval of the fourth or fifth. The diminished seventh chord on the sharpened second scale degree, ♯IIo7, may be used as a substitute dominant, [11] for example in C: ♯IIo7 = D♯–F♯–A–C♮ ↔ B–D♯–F♯–A = VII7.
In a tritone substitution , the substitute chord only differs slightly from the original chord. If the original chord in a song is G7 (G, B, D, F), the tritone substitution would be D♭7 (D♭, F, A♭, C♭). Note that the 3rd and 7th notes of the G7 chord are found in the D♭7 chord (albeit with a change of role). The tritone substitution is widely used for V7 chords in the popular jazz chord progression "ii-V-I". In the key of C, this progression is "d minor, G7, C Major". With tritone substitution, this progression would become "d minor, D♭7, C Major," which contains chromatic root movement. When performed by the bass player, this chromatic root movement creates a smooth-sounding progression. "Tritone substitutions and altered dominants are nearly identical...Good improvisers will liberally sprinkle their solos with both devices. A simple comparison of the notes generally used with the given chord [notation] and the notes used in tri-tone substitution or altered dominants will reveal a rather stunning contrast, and could cause the unknowledgeable analyzer to suspect errors. ...(the distinction between the two [tri-tone substitution and altered dominant] is usually a moot point).". [12]
Tonic substitution is the use of chords that sound similar to the tonic chord (or I chord) in place of the tonic. In major keys, the chords iii and vi are often substituted for the I chord, to add interest. In the key of C major, the I major 7 chord is "C, E, G, B," the iii chord ("III–7" [11] ) is E minor 7 ("E, G, B, D") and the vi minor 7 chord is A minor 7 ("A, C, E, G"). Both of the tonic substitute chords use notes from the tonic chord, which means that they usually support a melody originally designed for the tonic (I) chord.
The relative major/minor substitution shares two common tones and is so called because it involves the relation between major and minor keys with the same key signatures, such as C major and A minor. [13]
The augmented triad on the fifth scale degree may be used as a substitute dominant, and may also be considered as ♭III+, [14] for example in C: V+ = G–B–D♯, ♭III+ = E♭–G–B♮, and since in every key: D♯ = E♭.
The chord a minor third above, ♭VII7, may be substituted for the dominant, and may be preceded by its ii: iv7. [16] Due to common use the two chords of the backdoor progression (IV7-♭VII7) may be substituted for the dominant chord. [11] In C major the dominant would be G7: GBDF, sharing two common tones with B♭7: B♭DFA♭. A♭ and F serve as upper leading-tones back to G and E, respectively, rather than B♮ and F serving as the lower and upper leading-tones to C and E.
In jazz, chord substitutions can be applied by composers, arrangers, or performers. Composers may use chord substitutions when they are basing a new jazz tune on an existing chord progression from an old jazz standard or a song from a musical; arrangers for a big band or jazz orchestra may use chord substitutions in their arrangement of a tune, to add harmonic interest or give a different "feel" to a song; and instrumentalists may use chord substitutions in their performance of a song. Given that many jazz songs have repetition of internal sections, such as with a 32-bar AABA song form, performers or arrangers may use chord substitution within the A sections to add variety to the song.
Jazz comping instruments (piano, guitar, organ, vibes) often use chord substitution to add harmonic interest to a jazz tune with slow harmonic change. For example, the jazz standard chord progression of "rhythm changes" uses a simple eight bar chord progression in the bridge with the chords III7, VI7, II7, V7; in the key of B♭, these chords are D7, G7, C7, and F7 (each for two bars). A jazz guitarist might add a ii–V7 aspect to each chord, which would make the progression: "a minor, D7, d minor, G7, g minor, C7, c minor, F7. Alternatively, tritone substitutions could be applied to the progression.
Note that both the back door progression and ♯IIo7, when substituted for V7, introduces notes that seem wrong or anachronistic to the V7 chord (such as the fourth and the major seventh). They work only because the given instances of those chords are familiar to the ear; hence when an improviser uses them against the V7, the listener's ear hears the given precedents for the event, instead of the conflict with the V7.
— Coker (1997), p. 82 [11]
Theoretically, any chord can substitute for any other chord, as long as the new chord supports the melody. In practice, though, only a few options sound musically and stylistically appropriate to a given melody. This technique is used in music such as bebop or fusion to provide more sophisticated harmony, or to create a new-sounding re-harmonization of an old jazz standard.
Jazz soloists and improvisers also use chord substitutions to help them add interest to their improvised solos. Jazz soloing instruments that can play chords, such as jazz guitar, piano, and organ players may use substitute chords to develop a chord solo over an existing jazz tune with slow-moving harmonies. Also, jazz improvisers may use chord substitution as a mental framework to help them create more interesting-sounding solos. For example, a saxophonist playing an improvised solo over the basic "rhythm changes" bridge (in B♭, this is "D7, G7, C7, and F7", each for two bars) might think of a more complex progression that uses substitute chords (e.g., "a minor, D7, d minor, G7, g minor, C7, c minor, F7). In doing so, this implies the substitute chords over the original progression, which adds interest for listeners.
In music theory, the minor scale is three scale patterns – the natural minor scale, the harmonic minor scale, and the melodic minor scale – rather than just two as with the major scale, which also has a harmonic form but lacks a melodic form.
In music theory, a leading-tone is a note or pitch which resolves or "leads" to a note one semitone higher or lower, being a lower and upper leading-tone, respectively. Typically, the leading tone refers to the seventh scale degree of a major scale, a major seventh above the tonic. In the movable do solfège system, the leading-tone is sung as ti.
An altered chord is a chord that replaces one or more notes from the diatonic scale with a neighboring pitch from the chromatic scale. By the broadest definition, any chord with a non-diatonic chord tone is an altered chord. The simplest example of altered chords is the use of borrowed chords, chords borrowed from the parallel key, and the most common is the use of secondary dominants. As Alfred Blatter explains, "An altered chord occurs when one of the standard, functional chords is given another quality by the modification of one or more components of the chord."
In a musical composition, a chord progression or harmonic progression is a succession of chords. Chord progressions are the foundation of harmony in Western musical tradition from the common practice era of Classical music to the 21st century. Chord progressions are the foundation of popular music styles, traditional music, as well as genres such as blues and jazz. In these genres, chord progressions are the defining feature on which melody and rhythm are built.
A jazz scale is any musical scale used in jazz. Many "jazz scales" are common scales drawn from Western European classical music, including the diatonic, whole-tone, octatonic, and the modes of the ascending melodic minor. All of these scales were commonly used by late nineteenth and early twentieth-century composers such as Rimsky-Korsakov, Debussy, Ravel and Stravinsky, often in ways that directly anticipate jazz practice. Some jazz scales, such as the bebop scales, add additional chromatic passing tones to the familiar diatonic scales.
A chord, in music, is any harmonic set of pitches/frequencies consisting of multiple notes that are heard as if sounding simultaneously. For many practical and theoretical purposes, arpeggios and broken chords, or sequences of chord tones, may also be considered as chords in the right musical context.
In music, modulation is the change from one tonality to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest. Treatment of a chord as the tonic for less than a phrase is considered tonicization.
Modulation is the essential part of the art. Without it there is little music, for a piece derives its true beauty not from the large number of fixed modes which it embraces but rather from the subtle fabric of its modulation.
A secondary chord is an analytical label for a specific harmonic device that is prevalent in the tonal idiom of Western music beginning in the common practice period: the use of diatonic functions for tonicization.
In music theory, a dominant seventh chord, or major minor seventh chord, is a seventh chord, usually built on the fifth degree of the major scale, and composed of a root, major third, perfect fifth, and minor seventh. Thus it is a major triad together with a minor seventh, denoted by the letter name of the chord root and a superscript "7". An example is the dominant seventh chord built on G, written as G7, having pitches G–B–D–F:
The diminished seventh chord is a four-note chord composed of a root note, together with a minor third, a diminished fifth, and a diminished seventh above the root:. For example, the diminished seventh chord built on C, commonly written as Co7, has pitches C–E♭–G♭–B :
The tritone substitution is a common chord substitution found in both jazz and classical music. Where jazz is concerned, it was the precursor to more complex substitution patterns like Coltrane changes. Tritone substitutions are sometimes used in improvisation—often to create tension during a solo. Though examples of the tritone substitution, known in the classical world as an augmented sixth chord, can be found extensively in classical music since the Renaissance period, they were not heard until much later in jazz by musicians such as Dizzy Gillespie and Charlie Parker in the 1940s, as well as Duke Ellington, Art Tatum, Coleman Hawkins, Roy Eldridge and Benny Goodman.
Jazz harmony is the theory and practice of how chords are used in jazz music. Jazz bears certain similarities to other practices in the tradition of Western harmony, such as many chord progressions, and the incorporation of the major and minor scales as a basis for chordal construction. In jazz, chords are often arranged vertically in major or minor thirds, although stacked fourths are also quite common. Also, jazz music tends to favor certain harmonic progressions and includes the addition of tensions, intervals such as 9ths, 11ths, and 13ths to chords. Additionally, scales unique to style are used as the basis of many harmonic elements found in jazz. Jazz harmony is notable for the use of seventh chords as the basic harmonic unit more often than triads, as in classical music. In the words of Robert Rawlins and Nor Eddine Bahha, "7th chords provide the building blocks of jazz harmony."
Jazz chords are chords, chord voicings and chord symbols that jazz musicians commonly use in composition, improvisation, and harmony. In jazz chords and theory, most triads that appear in lead sheets or fake books can have sevenths added to them, using the performer's discretion and ear. For example, if a tune is in the key of C, if there is a G chord, the chord-playing performer usually voices this chord as G7. While the notes of a G7 chord are G–B–D–F, jazz often omits the fifth of the chord—and even the root if playing in a group. However, not all jazz pianists leave out the root when they play voicings: Bud Powell, one of the best-known of the bebop pianists, and Horace Silver, whose quintet included many of jazz's biggest names from the 1950s to the 1970s, included the root note in their voicings.
In music, the axis system is a system of analysis originating in the work of Ernő Lendvai, which he developed in his analysis of the music of Béla Bartók.
In music theory, the half-diminished seventh chord is a seventh chord composed of a root note, together with a minor third, a diminished fifth, and a minor seventh. For example, the half-diminished seventh chord built on C, commonly written as Cm7(♭5), or Cø7, has pitches C–E♭–G♭–B♭:
In jazz, a turnaround is a passage at the end of a section which leads to the next section. This next section is most often the repetition of the previous section or the entire piece or song.
The ii–V–I progression is a common cadential chord progression used in a wide variety of music genres, including jazz harmony. It is a succession of chords whose roots descend in fifths from the second degree (supertonic) to the fifth degree (dominant), and finally to the tonic. In a major key, the supertonic triad (ii) is minor, and in a minor key it is diminished. The dominant is, in its normal form, a major triad and commonly a dominant seventh chord. With the addition of chord alterations, substitutions, and extensions, limitless variations exist on this simple formula.
In music, harmonization is the chordal accompaniment to a line or melody: "Using chords and melodies together, making harmony by stacking scale tones as triads".
Musicians use various kinds of chord names and symbols in different contexts to represent musical chords. In most genres of popular music, including jazz, pop, and rock, a chord name and its corresponding symbol typically indicate one or more of the following:
The jazz minor scale is a derivative of the melodic minor scale, except only the ascending form of the scale is used. As the name implies, it is primarily used in jazz. It may be derived from the major scale with a minor third, making it a synthetic scale, and features a dominant seventh chord on the fifth degree (V) like the harmonic minor scale.