Circle of fifths

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Circle of fifths showing major and minor keys Circle of fifths deluxe 4.svg
Circle of fifths showing major and minor keys
Nikolay Diletsky's circle of fifths in Idea grammatiki musikiyskoy (Moscow, 1679) Diletsky circle.jpg
Nikolay Diletsky's circle of fifths in Idea grammatiki musikiyskoy (Moscow, 1679)

In music theory, the circle of fifths is a way of organizing the 12 chromatic pitches as a sequence of perfect fifths. If C is chosen as a starting point, the sequence is: C, G, D, A, E, B (=C), F (=G), C (=D), A, E, B, F. Continuing the pattern from F returns the sequence to its starting point of C. This order places the most closely related key signatures adjacent to one another. It is usually illustrated in the form of a circle.

Contents

Definition

The circle of fifths organizes pitches in a sequence of perfect fifths, generally shown as a circle with the pitches (and their corresponding keys) in a clockwise progression. Musicians and composers often use the circle of fifths to describe the musical relationships between pitches. Its design is helpful in composing and harmonizing melodies, building chords, and modulating to different keys within a composition. [1]

Using the system of just intonation, a perfect fifth consists of two pitches with a frequency ratio of 3:2, but generating a twelve perfect fifths in this way does not result in a return to the pitch class of the starting note. To adjust for this, instruments are generally tuned with the equal temperament system. Twelve equal-temperament fifths lead to a note exactly seven octaves above the initial tone—this results in a perfect fifth that is equivalent to seven equal-temperament semitones.

The top of the circle shows the key of C Major, with no sharps or flats. Proceeding clockwise, the pitches ascend by fifths. The key signatures associated with those pitches also change: the key of G has one sharp, the key of D has 2 sharps, and so on. Similarly, proceeding counterclockwise from the top of the circle, the notes change by descending fifths and the key signatures change accordingly: the key of F has one flat, the key of B has 2 flats, and so on. Some keys (at the bottom of the circle) can be notated either in sharps or in flats.

Starting at any pitch and ascending by a fifth generates all twelve tones before returning to the beginning pitch class (a pitch class consists of all of the notes indicated by a given letter regardless of octave—all "C"s, for example, belong to the same pitch class). Moving counterclockwise, the pitches descend by a fifth, but ascending by a perfect fourth will lead to the same note an octave higher (therefore in the same pitch class). Moving counter-clockwise from C could be thought of as descending by a fifth to F, or ascending by a fourth to F.

Structure and use

Diatonic key signatures

Each of the twelve pitches can serve as the tonic of a major or minor key, and each of these keys will have a diatonic scale associated with it. The circle diagram shows the number of sharps or flats in each key signature, with the major key indicated by a capital letter and the minor key indicated by a lower-case letter. Major and minor keys that have the same key signature are referred to as relative major and relative minor of one another.

Modulation and chord progression

Tonal music often modulates to a new tonal center whose key signature differs from the original by only one flat or sharp. These closely-related keys are a fifth apart from each other and are therefore adjacent in the circle of fifths. Chord progressions also often move between chords whose roots are related by perfect fifth, making the circle of fifths useful in illustrating the "harmonic distance" between chords.

The circle of fifths is used to organize and describe the harmonic function of chords. Chords can progress in a pattern of ascending perfect fourths (alternately viewed as descending perfect fifths) in "functional succession". This can be shown "...by the circle of fifths (in which, therefore, scale degree II is closer to the dominant than scale degree IV)". [2] In this view the tonic is considered the end point of a chord progression derived from the circle of fifths.

ii-V-I progression, in C Play subdominant, supertonic seventh, and supertonic chords (help*info)
illustrating the similarity between them. Ii-V-I turnaround in C.png
ii–V–I progression, in C Loudspeaker.svg Play subdominant, supertonic seventh, and supertonic chords   illustrating the similarity between them.

According to Richard Franko Goldman's Harmony in Western Music, "the IV chord is, in the simplest mechanisms of diatonic relationships, at the greatest distance from I. In terms of the [descending] circle of fifths, it leads away from I, rather than toward it." [3] He states that the progression I–ii–V–I (an authentic cadence) would feel more final or resolved than I–IV–I (a plagal cadence). Goldman [4] concurs with Nattiez, who argues that "the chord on the fourth degree appears long before the chord on II, and the subsequent final I, in the progression I–IV–viio–iii–vi–ii–V–I", and is farther from the tonic there as well. [5] (In this and related articles, upper-case Roman numerals indicate major triads while lower-case Roman numerals indicate minor triads.)

Circle closure in non-equal tuning systems

Using the exact 3:2 ratio of frequencies to define a perfect fifth (just intonation) does not quite result in a return to the pitch class of the starting note after going around the circle of fifths. Equal temperament tuning produces fifths that return to a tone exactly seven octaves above the initial tone and makes the frequency ratio of each half step the same. An equal-tempered fifth has a frequency ratio of 27/12:1 (or about 1.498307077:1), approximately two cents narrower than a justly tuned fifth at a ratio of 3:2.

Ascending by justly tuned fifths fails to close the circle by an excess of approximately 23.46 cents, roughly a quarter of a semitone, an interval known as the Pythagorean comma. In Pythagorean tuning, this problem is solved by markedly shortening the width of one of the twelve fifths, which makes it severely dissonant. This anomalous fifth is called the wolf fifth - a humorous reference to a wolf howling an off-pitch note. The quarter-comma meantone tuning system uses eleven fifths slightly narrower than the equally tempered fifth, and requires a much wider and even more dissonant wolf fifth to close the circle. More complex tuning systems based on just intonation, such as 5-limit tuning, use at most eight justly tuned fifths and at least three non-just fifths (some slightly narrower, and some slightly wider than the just fifth) to close the circle. Other tuning systems use up to 53 tones (the original 12 tones and 42 more between them) in order to close the circle of fifths.

History

Heinichen's musical circle (German: Musicalischer Circul) (1711) Heinichen musicalischer circul.png
Heinichen's musical circle (German: Musicalischer Circul) (1711)

Some sources imply that Pythagoras invented the circle of fifths in the sixth century B.C. but there is no proof of this. [6] [7] [8] Pythagoras was primarily concerned with the theoretical science of harmonics and is credited with having devised a system of tuning based upon the interval of a fifth, but did not tune more than eight notes, and left no written records of his work. [9]

In the late 1670s Ukrainian composer and theorist Nikolay Diletsky wrote a treatise on composition entitled Grammatika, "the first of its kind, aimed at teaching a Russian audience how to write Western-style polyphonic compositions." It taught how to write kontserty, polyphonic a cappella works usually based on liturgical texts and created by putting together musical sections with contrasting rhythm, meter, melodic material and vocal groupings. Diletsky intended his treatise to be a guide to composition using rules of music theory. The first circle of fifths appears in the Grammatika and it was used for students as a composition tool. [10]

Use

In musical pieces from the Baroque music era and the Classical era of music and in Western popular music, traditional music and folk music, when pieces or songs modulate to a new key, these modulations are often associated with the circle of fifths.

In practice, compositions rarely make use of the entire circle of fifths. More commonly, composers make use of "the compositional idea of the 'cycle' of 5ths, when music moves consistently through a smaller or larger segment of the tonal structural resources which the circle abstractly represents." [11] The usual practice is to derive the circle of fifths progression from the seven tones of the diatonic scale, rather from the full range of twelve tones present in the chromatic scale. In this diatonic version of the circle, one of the fifths is not a true fifth: it is a tritone (or a diminished fifth), e.g. between F and B in the "natural" diatonic scale (i.e. without sharps or flats). Here is how the circle of fifths derives, through permutation from the diatonic major scale:

Diatonic scale and the circle of fifths derived from it – major
Diatonic scale and the circle of fifths derived from it - major Diatonic scale and the circle of fifths derived from it - major.png
Diatonic scale and the circle of fifths derived from it – major

And from the (natural) minor scale:

Diatonic scale and the circle of fifths derived from it – minor
Diatonic scale and the circle of fifths derived from it - minor Diatonic scale and the circle of fifths derived from it - minor.png
Diatonic scale and the circle of fifths derived from it – minor

The following is the basic sequence of chords that can be built over the major bass-line:

Circle of fifths chord progression – major
Circle of fifths chord progression - major Circle of fifths chord progression - major.png
Circle of fifths chord progression – major

And over the minor:

Circle of fifths chord progression – minor
Circle of fifths chord progression - minor Circle of fifths chord progression - minor.png
Circle of fifths chord progression – minor

Adding sevenths to the chords creates a greater sense of forward momentum to the harmony:

Circle of fifths chord progression – minor with added sevenths
Circle of fifths chord progression - minor with added sevenths Circle of fifths chord progression - minor with added sevenths.png
Circle of fifths chord progression – minor with added sevenths

Baroque era

According to Richard Taruskin, Arcangelo Corelli was the most influential composer to establish the pattern as a standard harmonic "trope": "It was precisely in Corelli's time, the late seventeenth century, that the circle of fifths was being 'theorized' as the main propellor of harmonic motion, and it was Corelli more than any one composer who put that new idea into telling practice." [12]

The circle of fifths progression occurs frequently in the music of J. S. Bach. In the following, from Jauchzet Gott in allen Landen, BWV 51, even when the solo bass line implies rather than states the chords involved:

Bach from Cantata 51 bass line
Bach from Cantata 51 Bach from Cantata 51 bass line.png
Bach from Cantata 51

Handel uses a circle of fifths progression as the basis for the Passacaglia movement from his Harpsichord suite No. 6 in G minor.

Handel Passacaille from Suite in G minor bars 1–4
Handel Passacaille from Suite in G minor bars 1-4 Handel Passacaille from Suite in G minor bars 1-4.png
Handel Passacaille from Suite in G minor bars 1–4

Baroque composers learnt to enhance the "propulsive force" of the harmony engendered by the circle of fifths "by adding sevenths to most of the constituent chords." "These sevenths, being dissonances, create the need for resolution, thus turning each progression of the circle into a simultaneous reliever and re-stimulator of harmonic tension... Hence harnessed for expressive purposes." [13] Striking passages that illustrate the use of sevenths occur in the aria "Pena tiranna" in Handel's 1715 opera Amadigi di Gaula :

Handel, aria "Pena tiranna" from Amadigi. Orchestral introduction.
Handel, aria "Pena tiranna" from Amadigi. Orchestral introduction Handel, aria "Pena tiranna" from Amadigi. Orchestral introduction.png
Handel, aria "Pena tiranna" from Amadigi. Orchestral introduction

– and in Bach's keyboard arrangement of Alessandro Marcello's Concerto for Oboe and Strings.

Bach adagio BWV 974 (after Marcello)
Bach adagio BWV 974 (after Marcello) Bach adagio BWV 975 (after Marcello).png
Bach adagio BWV 974 (after Marcello)

Nineteenth century

During the nineteenth century, composers made use of the circle of fifths to enhance the expressive character of their music. Franz Schubert's poignant Impromptu in E flat major, D899, contains such a passage:

Schubert Impromptu in E flat
Schubert Impromptu in E flat Schubert Impromptu in E flat 02.png
Schubert Impromptu in E flat

– as does the Intermezzo movement from Mendelssohn's String Quartet No.2:

Mendelssohn String Quartet 2, 3rd movement (Intermezzo)
Mendelssohn String Quartet 2, 3rd movement (Intermezzo) Mendelssohn String Quartet 2, 3rd movement (Intermezzo).png
Mendelssohn String Quartet 2, 3rd movement (Intermezzo)

Robert Schumann's evocative "Child falling asleep" from his Kinderszenen springs a surprise at the end of the progression: the piece ends on an A minor chord, instead of the expected tonic E minor.

Schumann, Kind im Einschlummern (Child falling asleep)
Schumann, Kind im Einschlummern Schumann, Kind im Einschlummern.png
Schumann, Kind im Einschlummern

In Wagner's opera, Götterdämmerung, a cycle of fifths progression occurs in the music which transitions from the end of the prologue into the first scene of Act 1, set in the imposing hall of the wealthy Gibichungs. "Status and reputation are written all over the motifs assigned to Gunther", [14] chief of the Gibichung clan:

Wagner, Götterdämmerung, transition between the end of the Prologue and Act 1 scene 1
Wagner, Gotterdammerung, transition between the end of the Prologue and Act 1 scene 1 Wagner, Gotterdamerung, transition between the end of the Prologue and Act 1 scene 1.png
Wagner, Götterdämmerung, transition between the end of the Prologue and Act 1 scene 1

Ravel's "Pavane for a Dead Infanta", uses the cycle of fifths to evoke Baroque harmony to convey regret and nostalgia for a past era. The composer described the piece as "an evocation of a pavane that a little princess (infanta) might, in former times, have danced at the Spanish court.": [15]

Ravel, Pavane pour une Infante Défunte
Ravel Pavane pour une Infante Defunte Ravel Pavane pour une infante defunte.png
Ravel Pavane pour une Infante Défunte

The enduring popularity of the circle of fifths as both a form-building device and as an expressive musical trope is evident in the number of "standard" popular songs composed during the twentieth century. It is also favored as a vehicle for improvisation by jazz musicians.

The song opens with a pattern of descending phrases – in essence, the hook of the song – presented with a soothing predictability, almost as if the future direction of the melody is dictated by the opening five notes. The harmonic progression, for its part, rarely departs from the circle of fifths. [16]

Diatonic circle of fifths

The diatonic circle of fifths is the circle of fifths encompassing only members of the diatonic scale. Therefore, it contains a diminished fifth, in C major between B and F. See structure implies multiplicity. The circle progression is commonly a circle of fifths through the diatonic chords, including one diminished chord. A circle progression in C major with chords I–IV–viio–iii–vi–ii–V–I is shown below.

Chromatic circle

The circle of fifths is closely related to the chromatic circle, which also arranges the twelve equal-tempered pitch classes in a circular ordering. A key difference between the two circles is that the chromatic circle can be understood as a continuous space where every point on the circle corresponds to a conceivable pitch class, and every conceivable pitch class corresponds to a point on the circle. By contrast, the circle of fifths is fundamentally a discrete structure, and there is no obvious way to assign pitch classes to each of its points. In this sense, the two circles are mathematically quite different.

However, the twelve equal-tempered pitch classes can be represented by the cyclic group of order twelve, or equivalently, the residue classes modulo twelve, . The group has four generators, which can be identified with the ascending and descending semitones and the ascending and descending perfect fifths. The semitonal generator gives rise to the chromatic circle while the perfect fifth gives rise to the circle of fifths.

Relation with chromatic scale

The circle of fifths drawn within the chromatic circle as a star dodecagram. Pitch class space star.svg
The circle of fifths drawn within the chromatic circle as a star dodecagram.

The circle of fifths, or fourths, may be mapped from the chromatic scale by multiplication, and vice versa. To map between the circle of fifths and the chromatic scale (in integer notation) multiply by 7 (M7), and for the circle of fourths multiply by 5 (P5).

Here is a demonstration of this procedure. Start off with an ordered 12-tuple (tone row) of integers

(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)

representing the notes of the chromatic scale: 0 = C, 2 = D, 4 = E, 5 = F, 7 = G, 9 = A, 11 = B, 1 = C, 3 = D, 6 = F, 8 = G, 10 = A. Now multiply the entire 12-tuple by 7:

(0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77)

and then apply a modulo 12 reduction to each of the numbers (subtract 12 from each number as many times as necessary until the number becomes smaller than 12):

(0, 7, 2, 9, 4, 11, 6, 1, 8, 3, 10, 5)

which is equivalent to

(C, G, D, A, E, B, F, C, G, D, A, F)

which is the circle of fifths. Note that this is enharmonically equivalent to:

(C, G, D, A, E, B, G, D, A, E, B, F).

Enharmonic equivalents and theoretical keys

The key signatures found on the bottom of the circle of fifths diagram, such as D major, are often written one way in flats and in another way using sharps. These keys are easily interchanged using enharmonic equivalents. Enharmonic means that the notes sound the same, but are written differently. For example, the key signature of D major, with five flats, contains the same sounding notes, enharmonically, as C major (seven sharps).

After C comes the key of G (following the pattern of being a fifth higher, and, coincidentally, enharmonically equivalent to the key of A). The "eighth sharp" is placed on the F, to make it F DoubleSharp.svg . The key of D, with nine sharps, has another sharp placed on the C, making it C DoubleSharp.svg . The same is true for key signatures with flats; The key of E (four sharps) is equivalent to the key of F (again, one fifth below the key of C, following the pattern of flat key signatures). The last flat is placed on the B, making it B Doubleflat.svg . Such keys with double accidentals in the key signatures are called theoretical keys: the appearance of their key signatures is extremely rare, but they are sometimes tonicised in the course of a work (particularly if the home key was already heavily sharped or flatted).

There does not appear to be a standard on how to notate theoretical key signatures:

See also

Notes

  1. Michael Pilhofer and Holly Day (23 Feb 2009). "The Circle of Fifths: A Brief History", www.dummies.com.
  2. Nattiez 1990, p. 225.
  3. Goldman 1965 , p. 68.
  4. Goldman 1965 , chapter 3.
  5. Nattiez 1990 , p. 226.
  6. Anon. "The Circle of Fifths: A Brief History". Dummies.com.[ failed verification ]
  7. https://www.classicfm.com/discover-music/music-theory/what-is-the-circle-of-fifths/.Missing or empty |title= (help)[ failed verification ]
  8. Anon. (2016). "The Circle of Fifths".[ failed verification ]
  9. Fraser, Peter A. (2001). "The Development of Musical Tuning Systems" (PDF): 9, 13. Retrieved 24 May 2020.Cite journal requires |journal= (help) (archive from 1 July 2013).
  10. Jensen 1992 , pp. 306–307.
  11. Whittall, A. (2002, p. 259) "Circle of Fifths", article in Latham, E. (ed.) The Oxford Companion to Music. Oxford University Press.
  12. Taruskin, R. (2010, p. 184) The Oxford History of Western Music: Music in the Seventeenth and Eighteenth centuries. Oxford University Press.
  13. Taruskin, R. (2010, p. 188) The Oxford History of Western Music: Music in the Seventeenth and Eighteenth centuries. Oxford University Press.
  14. Scruton, R. (2016, p. 121) The Ring of Truth: The Wisdom of Wagner's Ring of the Nibelung. London, Allen Lane.
  15. Andres, Robert, "An introduction to the solo piano music of Debussy and Ravel", BBC Radio 3, accessed 17 November 2011
  16. Gioa, T. (2012, p.115) The Jazz Standards; a Guide to the repertoire. Oxford University Press.
  17. Gioa, T. (2012, p.16) The Jazz Standards; a Guide to the repertoire. Oxford University Press.
  18. Scott, Richard J. (2003, p. 123) Chord Progressions for Songwriters. Bloomington Indiana, Writers Club Press.
  19. Kostka, Stefan; Payne, Dorothy; Almén, Byron (2013). Tonal harmony with an introduction to twentieth-century music (7th ed.). New York: McGraw-Hill. pp. 46, 238. ISBN   978-0-07-131828-0.
  20. "You Never Give Me Your Money" (1989, p1099-1100, bars 1-16) The Beatles Complete Scores. Hal Leonard.
  21. Oakes, Tim (June 1980). "Mike Oldfield". International Musician and Recording World. Retrieved 19 February 2021 via Tubular.net.
  22. Fekaris, D. and Perren, F.J. (1978) I Will Survive. Polygram International Publishing.
  23. Tennant, N. and Lowe, C. (1987, bars 1-8) "It's a Sin." Sony/ATV Music Publishing (UK) Ltd.
  24. Moroder, G., Bellote, P. and Summer, D. (1975, bars 11-14) "Love to Love you, Baby" copyright 1976, Bulle Music Inc.
  25. McCartin 1998, p. 364.
  26. https://www.hickeys.com/music/brass/brass_ensembles/brass_quintets/products/sku035994-ewald-victor-quintet-no-4-in-ab-op-8.php

Related Research Articles

Just intonation Musical tuning based on pure intervals

In music, just intonation or pure intonation is the tuning of musical intervals as whole number ratios of frequencies. Any interval tuned in this way is called a just interval. Just intervals consist of members of a single harmonic series of a (lower) implied fundamental. For example, in the diagram, the notes G and middle C are both members of the harmonic series of the lowest C and their frequencies will be 3 and 4 times, respectively, the fundamental frequency; thus, their interval ratio will be 4:3. If the frequency of the fundamental is 50 Hertz, the frequencies of the two notes in question would be 150 and 200.

Key signature Set of musical alterations

In Western musical notation, a key signature is a set of sharp, flat, or rarely, natural symbols placed on the staff at the beginning of a section of music. The initial key signature in a piece is placed immediately after the clef at the beginning of the first line. If the piece contains a section in a different key, the new key signature is placed at the beginning of that section.

Major scale Diatonic scale made of seven notes

The major scale is one of the most commonly used musical scales, especially in Western music. It is one of the diatonic scales. Like many musical scales, it is made up of seven notes: the eighth duplicates the first at double its frequency so that it is called a higher octave of the same note.

In music theory, the term minor scale refers to three scale patterns – the natural minor scale, the harmonic minor scale, and the melodic minor scale – rather than just one as with the major scale.

In music theory, an interval is the difference in pitch between two sounds. An interval may be described as horizontal, linear, or melodic if it refers to successively sounding tones, such as two adjacent pitches in a melody, and vertical or harmonic if it pertains to simultaneously sounding tones, such as in a chord.

Chromatic scale Musical scale with twelve pitches separated by semitone intervals

The chromatic scale is a set of twelve pitches used in tonal music, with notes separated by the interval of a semitone. Almost all western musical instruments, such as the piano, are made to produce the chromatic scale, while other instruments such as the trombone and violin can also produce microtones, or notes between those available on a piano.

In music theory, the tritone is defined as a musical interval composed of three adjacent whole tones. For instance, the interval from F up to the B above it is a tritone as it can be decomposed into the three adjacent whole tones F–G, G–A, and A–B. According to this definition, within a diatonic scale there is only one tritone for each octave. For instance, the above-mentioned interval F–B is the only tritone formed from the notes of the C major scale. A tritone is also commonly defined as an interval spanning six semitones. According to this definition, a diatonic scale contains two tritones for each octave. For instance, the above-mentioned C major scale contains the tritones F–B and B–F. In twelve-equal temperament, the tritone divides the octave exactly in half as 6 of 12 semitones or 600 of 1200 cents.

In music theory, the key of a piece is the group of pitches, or scale, that forms the basis of a music composition in classical, Western art, and Western pop music.

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. Thus, the enharmonic spelling of a written note, interval, or chord is an alternative way to write that note, interval, or chord. The term is derived from Latin enharmonicus, from Late Latin enarmonius, from Ancient Greek ἐναρμόνιος (enarmónios), from ἐν (en)+ἁρμονία (harmonía).

Perfect fifth musical interval

In music theory, a perfect fifth is the musical interval corresponding to a pair of pitches with a frequency ratio of 3:2, or very nearly so.

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 Western popular music styles and traditional music. 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.

Chord (music) Harmonic set of three or more notes

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.

Modulation (music)

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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.

Semitone musical interval

A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically. It is defined as the interval between two adjacent notes in a 12-tone scale. For example, C is adjacent to C; the interval between them is a semitone.

Closely related key

In music, a closely related key is one sharing many common tones with an original key, as opposed to a distantly related key. In music harmony, there are five of them: they share all, or all except one, pitches with a key with which it is being compared, and is adjacent to it on the circle of fifths and its relative major or minor.

In the musical system of ancient Greece, Genus is a term used to describe certain classes of intonations of the two movable notes within a tetrachord. The tetrachordal system was inherited by the Latin medieval theory of scales and by the modal theory of Byzantine music; it may have been one source of the later theory of the jins of Arabic music. In addition, Aristoxenus calls some patterns of rhythm "genera".

Comma (music)

In music theory, a comma is a very small interval, the difference resulting from tuning one note two different ways. The word comma used without qualification refers to the syntonic comma, which can be defined, for instance, as the difference between an F tuned using the D-based Pythagorean tuning system, and another F tuned using the D-based quarter-comma meantone tuning system. Intervals separated by the ratio 81:80 are considered the same note because the 12-note Western chromatic scale does not distinguish Pythagorean intervals from 5-limit intervals in its notation. Other intervals are considered commas because of the enharmonic equivalences of a tuning system. For example, in 53TET, B and A are both approximated by the same interval although they are a septimal kleisma apart.

A heptatonic scale is a musical scale that has seven pitches per octave. Examples include the major scale or minor scale; e.g., in C major: C D E F G A B C—and in the relative minor, A minor, natural minor: A B C D E F G A; the melodic minor scale, A B C D E FGA ascending, A G F E D C B A descending; the harmonic minor scale, A B C D E F GA; and a scale variously known as the Byzantine, and Hungarian, scale, C D E F G A B C. Indian classical theory postulates seventy-two seven-tone scale types, collectively called thaat, whereas others postulate twelve or ten seven-tone scale types.

Diatonic and chromatic Terms in music theory to characterize scales

Diatonic and chromatic are terms in music theory that are most often used to characterize scales, and are also applied to musical instruments, intervals, chords, notes, musical styles, and kinds of harmony. They are very often used as a pair, especially when applied to contrasting features of the common practice music of the period 1600–1900.

References

Further reading