A seventh chord is a
chord
Chord may refer to:
* Chord (music), an aggregate of musical pitches sounded simultaneously
** Guitar chord a chord played on a guitar, which has a particular tuning
* Chord (geometry), a line segment joining two points on a curve
* Chord ( ...
consisting of a
triad
Triad or triade may refer to:
* a group of three
Businesses and organisations
* Triad (American fraternities), certain historic groupings of seminal college fraternities in North America
* Triad (organized crime), a Chinese transnational orga ...
plus a note forming an
interval of a
seventh above the chord's
root. When not otherwise specified, a "seventh chord" usually means a
dominant seventh chord
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 tog ...
: a
major triad together with a
minor seventh. However, a variety of sevenths may be added to a variety of triads, resulting in many different types of seventh chords.
In its earliest usage, the seventh was introduced solely as an
embellishing or nonchord tone. The seventh destabilized the triad, and allowed the composer to emphasize movement in a given direction. As time passed and the collective ear of the western world became more accustomed to
dissonance, the seventh was allowed to become a part of the chord itself, and in some modern music, jazz in particular, nearly every chord is a seventh chord. Additionally, the general acceptance of
equal temperament
An equal temperament is a musical temperament or tuning system, which approximates just intervals by dividing an octave (or other interval) into equal steps. This means the ratio of the frequencies of any adjacent pair of notes is the same, wh ...
during the 19th century reduced the dissonance of some earlier forms of sevenths.
Classification
Most textbooks name these chords ''formally'' by the type of triad and type of seventh; hence, a chord consisting of a major triad and a minor seventh above the root is referred to as a major/minor seventh chord. When the triad type and seventh type are identical (i.e. they are both major, minor, or diminished), the name is shortened. For instance, a ''major/major'' seventh is generally referred to as a major seventh. This rule is not valid for augmented chords: since the augmented/augmented chord is not commonly used, the abbreviation ''augmented'' is used for ''augmented/minor'', rather than ''augmented/augmented''. Additionally, ''half-diminished'' stands for ''diminished/minor'', and ''dominant'' stands for ''major/minor''. When the type is not specified at all, the triad is assumed to be major, and the seventh is understood as a minor seventh (e.g. a "C" chord is a "C major triad", and a "C
7" chord is a "
C major/minor seventh chord", also known as a "C dominant seventh chord"). For symbols used for seventh chords, see also .
Tertian
The most common chords are
tertian, constructed using a sequence of
major thirds (spanning 4
semitones) and/or
minor thirds (3 semitones). Since there are 3 third intervals in a seventh chord (4 notes) and each can be major or minor, there are 8 possible combinations. The five commonly found in western music are the major seventh, the minor (or minor/minor) seventh, the dominant (or major/minor) seventh, the half-diminished seventh, and the diminished seventh, technically not a tertian chord, with its
diminished third, but often listed with the tertian chords as commonly found. The less commonly found tertian is the minor/major seventh.
Non-tertian
Seventh chords can also be constructed using augmented or diminished thirds. These chords are not tertian and can be used in non-tertian harmony. There are many (mathematically, 64) chords that can be built, however, only a few of them are used in Western music.
In tuning systems other than
equal temperament
An equal temperament is a musical temperament or tuning system, which approximates just intervals by dividing an octave (or other interval) into equal steps. This means the ratio of the frequencies of any adjacent pair of notes is the same, wh ...
there are further possible seventh chords. In
just intonation
In music, just intonation or pure intonation is the tuning of musical intervals
Interval may refer to:
Mathematics and physics
* Interval (mathematics), a range of numbers
** Partially ordered set#Intervals, its generalization from numbers to ...
, for example, there is the
harmonic seventh.
Types
Dominant seventh chord
A dominant seventh chord, or major-minor seventh chord is a
chord
Chord may refer to:
* Chord (music), an aggregate of musical pitches sounded simultaneously
** Guitar chord a chord played on a guitar, which has a particular tuning
* Chord (geometry), a line segment joining two points on a curve
* Chord ( ...
composed of a
root,
major third,
perfect fifth
In music theory, a perfect fifth is the Interval (music), musical interval corresponding to a pair of pitch (music), pitches with a frequency ratio of 3:2, or very nearly so.
In classical music from Western culture, a fifth is the interval fro ...
, and
minor seventh. It can be also viewed as a
major triad with an additional
minor seventh. It is denoted using
popular music symbols by adding a superscript "7" after the letter designating the chord root.
The dominant seventh is found almost as often as the
dominant triad.
The chord can be represented by the
integer notation .
Of all the seventh chords, perhaps the most important is the dominant seventh. It was the first seventh chord to appear regularly in
classical music
Classical music generally refers to the art music of the Western world, considered to be distinct from Western folk music or popular music traditions. It is sometimes distinguished as Western classical music, as the term "classical music" also ...
. The name comes from the fact that the flat seventh occurs naturally in the scale built upon the root when it functions as the
dominant (i.e., the fifth
degree
Degree may refer to:
As a unit of measurement
* Degree (angle), a unit of angle measurement
** Degree of geographical latitude
** Degree of geographical longitude
* Degree symbol (°), a notation used in science, engineering, and mathematics
...
) of some major
diatonic scale
In music theory, a diatonic scale is any heptatonic scale that includes five whole steps (whole tones) and two half steps (semitones) in each octave, in which the two half steps are separated from each other by either two or three whole steps, ...
.
Take for example the C major scale (C, D, E, F, G, A, B, C):
The note G is the dominant degree of C major—its fifth note. When we arrange the notes of the C major scale in ascending pitch and use only these notes to build a seventh chord, and we start with G (not C), then the resulting chord contains the four notes G–B–D–F and is called G dominant seventh (G
7). The note F is a
minor seventh from G, and is also called the dominant seventh with respect to G.
Harmonic seventh chord
The harmonic seventh chord is a dominant seventh chord formed by a
major triad plus a harmonic seventh interval.
The harmonic seventh interval is a minor seventh tuned in the 7:4
pitch ratio, one of the possible "just ratios" defined for this interval in
just intonation
In music, just intonation or pure intonation is the tuning of musical intervals
Interval may refer to:
Mathematics and physics
* Interval (mathematics), a range of numbers
** Partially ordered set#Intervals, its generalization from numbers to ...
(slightly below the width of a minor seventh as tuned in
equal temperament
An equal temperament is a musical temperament or tuning system, which approximates just intervals by dividing an octave (or other interval) into equal steps. This means the ratio of the frequencies of any adjacent pair of notes is the same, wh ...
). With just intonation on all notes of the harmonic seventh chord, the ratio between the frequencies of the pitches in the chord is 4:5:6:7. For example, a justly intuned A harmonic seventh chord in root position starting at
A440 consists of the pitches 440 Hz, 550 Hz, 660 Hz, and 770 Hz.
Sometimes called a "blue note", the harmonic seventh is used by singers, through note bending on guitars, and on other instruments not restricted to equal temperament. An often heard example of the harmonic seventh chord is the last word of the modern addition to the song "Happy Birthday to You", with the lyrics, "and many more!" The harmony on the word "more" is typically sung as a harmonic seventh chord.
Frequent use of the harmonic seventh chord is one of the defining characteristics of
blues
Blues is a music genre and musical form which originated in the Deep South of the United States around the 1860s. Blues incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads from the Afr ...
and
barbershop harmony; barbershoppers refer to it as "the barbershop seventh". Since barbershop music tends to be sung in
just intonation
In music, just intonation or pure intonation is the tuning of musical intervals
Interval may refer to:
Mathematics and physics
* Interval (mathematics), a range of numbers
** Partially ordered set#Intervals, its generalization from numbers to ...
, the barbershop seventh chord may be accurately termed a harmonic seventh chord. The harmonic seventh chord is also widely used in blues-flavored music. As guitars, pianos, and other equal-temperament instruments cannot play this chord, it is frequently approximated by a dominant seventh. As a result, it is often called a dominant seventh chord and written with the same symbols (such as the blues progression I
7–V
7–IV
7).
Major and minor seventh chords
While the dominant seventh chord is typically built on the fifth (or dominant) degree of a major scale, the minor seventh chord is built on the second, third, or sixth degree. A minor seventh chord contains the same notes as an
added sixth chord. For example, C–E–G–B can function as both a C minor seventh and an E added sixth (Id chord).
Major seventh chords are usually constructed on the first or fourth degree of a scale, (in C or G major: C–E–G–B). Due to the major seventh interval between the root and seventh (C–B, an inverted minor second), this chord can sometimes sound dissonant, depending on the voicing used. For example,
Bacharach and
David's "
Raindrops Keep Fallin' on My Head" opens with a major chord followed by a major seventh in the next measure.
The major seventh is sometimes notated as 7 (a delta chord) or just a (which has the same meaning).
Half-diminished seventh chord
A half-diminished seventh chord is a seventh chord built from the seventh degree of a major scale. It is considered "half-diminished" because a fully diminished seventh has a double-flatted (diminished) seventh, making it
enharmonic
In modern musical notation and tuning, an enharmonic equivalent is a note, interval, or key signature that is equivalent to some other note, interval, or key signature but "spelled", or named differently. The enharmonic spelling of a written n ...
ally the same as a major sixth. The half-diminished seventh chord uses a minor seventh over the root of a diminished triad.
Example: (in the key of C major) B–D–F–A.
Diminished seventh chord
A diminished seventh chord is made of three superimposed minor thirds (e.g., B–D–F–A), which is two tritones a minor third apart (e.g., B–F, D–A). The diminished seventh chord has been used by composers and musicians for a variety of reasons over time. Some reasons include: as a symbol of
Sturm und Drang;
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
; and for characterisation. The diminished seventh chord is seen more frequently in late classical and romantic period works but is also found in
Baroque
The Baroque (, ; ) is a style of architecture, music, dance, painting, sculpture, poetry, and other arts that flourished in Europe from the early 17th century until the 1750s. In the territories of the Spanish and Portuguese empires including t ...
and
Renaissance period works, though not as frequently.
All of the elements of the diminished seventh chord can be found in the dominant seventh flat nine (79) chord as seen in a comparison of the two chords.
Inversions
:
There are four different
inversions of a seventh chord. Following
basso continuo
Basso continuo parts, almost universal in the Baroque era (1600–1750), provided the harmonic structure of the music by supplying a bassline and a chord progression. The phrase is often shortened to continuo, and the instrumentalists playing th ...
notation, the inversions are as follows:
*: GBDF
*: BDFG
*: DFGB
* or : FGBD
Additional numbers are used to indicate the seventh chords and their inversions.
[http://musictheory.alcorn.edu/Version2/theory1/seventhrom.htm]
See also
*
Dominant seventh flat five chord
*
Diminished major seventh chord
In music theory, a diminished major seventh chord is a seventh chord composed of a diminished triad and a major seventh.Jamini, Deborah. (2005). ''Harmony And Composition: Basics to Intermediate'', p.204. . Thus, it is composed of a root note, tog ...
*
Diminished minor seventh chord
In music theory, the half-diminished seventh chord (also known as a half-diminished chord or a minor seventh flat five chord) is a seventh chord composed of a root note, together with a minor third, a diminished fifth, and a minor seventh (1,&nbs ...
*
Augmented major seventh chord
In music, an augmented major seventh chord or major seventh sharp five chord is a seventh chord composed of a root, major third, augmented fifth, and major seventh (1, 3, 5, 7). It can be viewed as an augmented triad with an additional major seven ...
*
Augmented minor seventh chord
The augmented seventh chord, or seventh augmented fifth chord, or seventh sharp five chord is a seventh chord composed of a root, major third, augmented fifth, and minor seventh (1, 3, 5, 7).Garner, Robert (2007). ''Mel Bay Presents Essential Musi ...
References
External links
7th Chords on guitar fretjam.com
"17 Easy Jazz Guitar Chords For Beginners" Dirk Laukens, jazzguitar.be
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