In
music theory, the term
interval describes the difference in
pitch between two
notes. Although frequently used in connection with intervals, the term "
distance" does not adequately describe the physics and subjective effects of two interacting frequencies.
Intervals may be described as:
- vertical (or harmonic) if the two notes sound simultaneously
- linear (or melodic), if the notes sound successively.[1]
Interval class is a system of labelling intervals when the order of the notes is left unspecified, therefore describing an interval in terms of the shortest distance possible between its two
pitch classes.
[2]
Frequency ratios
Intervals may be labelled according to the
ratio of
frequencies of the two pitches. Important intervals are those using the lowest integers, such as 1/1, 2/1, 3/2, etc. This system is frequently used to describe intervals in non-Western music. This method is also often used in
just intonation, and in theoretical explanations of equal-tempered intervals used in European tonal music which explain their use through their approximation of just intervals.
Interval number and quality

Interval names
U = unison; 8ve = octave
In Western harmonic theory, intervals are labeled according to the number of
scale steps or
staff positions they encompass, as shown at right.
Intervals larger than an
octave are called
compound intervals; for example, a tenth is known as a compound third. Intervals larger than a thirteenth are rarely spoken of, since going above this by stacking thirds would result in a double octave (but see
8va for use of
15ma).
The name or the label of an interval is determined by counting the number of degrees between the two
notes beginning with one for the lower note. The number of degrees between F and B for example is 4, therefore the interval is a fourth.
The name of any interval is further qualified using the terms perfect,
major,
minor,
augmented, and
diminished. This is called its
interval quality.
- Unison, fourth, fifth, octave. These intervals may be perfect, augmented, or diminished.
- They are called perfect because of their extremely simple pitch relationships resulting in a high degree of consonance and also because when they are inverted they remain perfect (a perfect fourth inverts to a perfect fifth and vice versa).
- A perfect fourth is five semitones.
- A perfect fifth is seven semitones.
- A perfect octave is twelve semitones.
- A perfect unison occurs between notes of the same pitch, so it is zero semitones.
- In each case, an augmented interval contains one more semitone, a diminished interval one fewer.
- Second, third, sixth, seventh. These intervals may be major, minor, augmented, or diminished.
- A tritone is six semitones.
- Major seconds are two semitones, also called a whole step, minor seconds are one semitone, also called a half step.
- Major thirds are four semitones, minor thirds are three semitones.
- Major sixths are nine semitones, minor sixths are eight semitones.
- Major sevenths are eleven semitones, minor sevenths are ten semitones.
- In each case, the augmented interval contains one semitone more than the major interval, and the diminished interval one semitone fewer than the minor interval.
It is possible to have doubly-diminished and doubly-augmented intervals, but these are quite rare.
The name of an interval cannot be determined by counting semitones alone. There are four semitones between
B and
E♭ but this interval is not a major third, but rather a diminished fourth, a relatively rare interval (but which does appear naturally as part of the
harmonic minor scale). In
equal-tempered tuning, as on a piano, these intervals are indistinguishable by sound, but the
diatonic function of the notes incorporated might be very different.
Diatonic and chromatic intervals
A
diatonic interval is an interval formed by two notes of a diatonic scale. The table on the right depicts all diatonic intervals for C major. As the diatonic functions are similarly common to each and every major key, the contents of the table can be summarised as follows:
- All perfect, major and minor intervals are diatonic.
- Additionally, the tritone and the diminished 5th are diatonic.
- All other intervals are chromatic.
Shorthand notation
Intervals are often abbreviated with a
P for perfect,
m for
minor,
M for
major,
d for
diminished,
A for
augmented, followed by the diatonic interval number. The indication M and P are often omitted. The
octave is P8, and a
unison is usually referred to simply as "a unison" but can be labeled P1. The
tritone, an augmented fourth or diminished fifth is often
π or
TT. Examples:
- m2: minor second
- M3: major third
- P5: perfect fifth
- m9: minor ninth
For use in describing
chords, the sign
+ is used for augmented and
° for diminished. Furthermore the 3 for the third is often omitted, and for the seventh, the plain form stands for the minor interval, while the major is indicated by
maj. So for example:
- m: minor third
- 7: minor seventh
- °7: diminished seventh
- maj7: major seventh
- +5: augmented fifth
- °5: diminished fifth
Enharmonic intervals
Two intervals are considered to be
enharmonic, or
enharmonically equivalent, if they both contain the same
pitches spelled in different ways; that is, if the notes in the two intervals are themselves enharmonically equivalent. Enharmonic intervals span the same number of
semitones. For example, as shown in the matrix below, F♯–A♯ (a
major third), G♭–B♭ (also a major third), F♯–B♭ (a
diminished fourth), and G♭–A♯ (a double
augmented second) are all enharmonically equivalent — and they all span four semitones.
Steps and skips
Linear (melodic) intervals may be described as
steps or
skips in a diatonic context. Steps are linear intervals between consecutive
scale degrees while skips are not, although if one of the notes is
chromatically altered so that the resulting interval is three
semitones or more (e.g. C to D♯), that may also be considered a skip. However, the reverse is not true: a
diminished third, an interval comprising two
semitones, is still considered a skip.
The words
conjunct and
disjunct refer to melodies composed of steps and skips, respectively.
Pitch class intervals
Post-tonal or
atonal theory, originally developed for equal tempered European classical music written using the
twelve tone technique or
serialism,
integer notation is often used, most prominently in
musical set theory. In this system intervals are named according to the number of half steps, from 0 to 11, the largest interval class being 6.
Ordered and unordered pitch and pitch class intervals
In atonal or
musical set theory there are numerous types of intervals, the first being
ordered pitch interval, the distance between two pitches upward or downward. For instance, the interval from C to G upward is 7, but the interval from G to C downward is −7. One can also measure the distance between two pitches without taking into account direction with the unordered pitch interval, somewhat similar to the interval of tonal theory.
The interval between pitch classes may be measured with ordered and unordered pitch class intervals. The ordered one, also called directed interval, may be considered the measure upwards, which, since we are dealing with pitch classes, depends on whichever pitch is chosen as 0. For unordered pitch class interval see
interval class.
Generic and specific intervals
In
diatonic set theory,
specific and
generic intervals are distinguished. Specific intervals are the interval class or number of semitones between scale degrees or collection members, and generic intervals are the number of scale steps between notes of a collection or scale.
Cents
The standard system for comparing intervals of different sizes is with
cents. This is a
logarithmic scale in which the octave is divided into 1200 equal parts. In
equal temperament, each
semitone is exactly 100 cents.
The value in cents for the interval
f1 to
f2 is 1200×log
2(
f2/
f1).
Comparison of different interval naming systems
# semitones
|
Interval class |
Generic interval |
Common diatonic name |
Comparable just interval |
Comparison of interval width in cents
|
equal temperament |
just intonation |
quarter-comma meantone
|
| 0 | 0 | 0 | perfect unison | 1:1 | 0 | 0 | 0 |
| 1 | 1 | 1 | minor second | 16:15 | 100 | 112 | 117 |
| 2 | 2 | 1 | major second | 9:8 | 200 | 204 | 193 |
| 3 | 3 | 2 | minor third | 6:5 | 300 | 316 | 310 |
| 4 | 4 | 2 | major third | 5:4 | 400 | 386 | 386 |
| 5 | 5 | 3 | perfect fourth | 4:3 | 500 | 498 | 503 |
| 6 | 6 | 3 4 | augmented fourth diminished fifth | 45:32 64:45 | 600 | 590 610 | 579 621 |
| 7 | 5 | 4 | perfect fifth | 3:2 | 700 | 702 | 697 wolf fifth 737 |
| 8 | 4 | 5 | minor sixth | 8:5 | 800 | 814 | 814 |
| 9 | 3 | 5 | major sixth | 5:3 | 900 | 884 | 889 |
| 10 | 2 | 6 | minor seventh | 16:9 | 1000 | 996 | 1007 |
| 11 | 1 | 6 | major seventh | 15:8 | 1100 | 1088 | 1083 |
| 12 | 0 | 0 | perfect octave | 2:1 | 1200 | 1200 | 1200 |
It is possible to construct just intervals which are closer to the equal-tempered equivalents, but most of the ones listed above have been used historically in equivalent contexts. In particular the tritone (augmented fourth or diminished fifth), could have other ratios; 17:12 (603 cents) is fairly common. The 7:4 interval (the harmonic seventh) has been a contentious issue throughout the history of music theory; it is 31 cents flatter than an equal-tempered minor seventh. Some assert the 7:4 is one of the
blue notes used in
jazz.
In the diatonic system, every interval has one or more
enharmonic equivalents, such as
augmented second for
minor third.
Consonant and dissonant intervals
Consonance and dissonance are relative terms referring to the stability, or state of repose, of particular musical effects. Dissonant intervals would be those which cause tension and desire to be
resolved to consonant intervals.
These terms are relative to the usage of different compositional styles.
- In atonal music all intervals (or interval classes) are considered equally consonant melodically and harmonically.
- In the middle ages, only the octave and perfect fifth were considered consonant harmonically.
- In 16th-century usage, perfect fifths and octaves, and major and minor thirds and sixths were considered harmonically consonant, and all other intervals dissonant. In the common practice period, it makes more sense to speak of consonant and dissonant chords, and certain intervals previously thought to be dissonant (such as minor sevenths) became acceptable in certain contexts. However, 16th-century practice continued to be taught to beginning musicians throughout this period.
- Hermann von Helmholtz (1821–1894) defined a harmonically consonant interval as one in which the two pitches have an overtone in common (specifically excluding the seventh harmonic). This essentially defines all seconds and sevenths as dissonant, while perfect fourths and fifths, and major and minor thirds and sixths, are consonant.
- Pythagoras defined a hierarchy of consonance based on how small the numbers were which express the ratio. 20th-century composer and theorist Paul Hindemith's system has a hierarchy with the same results as Pythagoras's, but defined by fiat rather than by interval ratios, to better accommodate equal temperament, all of whose intervals (except the octave) would be dissonant using acoustical methods.
- David Cope (1997, p.40–41) suggests the concept of interval strength, in which an interval's strength, consonance, or stability is determined by its approximation to a lower and stronger, or higher and weaker, position in the harmonic series. See also: Lipps-Meyer law.
All of the above analyses refer to vertical (simultaneous) intervals.
Inversion
An interval may be
inverted, by raising the lower pitch an
octave, or lowering the upper pitch an octave (though it is less usual to speak of inverting unisons or octaves). For example, the fourth between a lower C and a higher F may be inverted to make a fifth, with a lower F and a higher C. Here are the ways to identify interval inversions:

Interval inversions
- For diatonically-named intervals[3] there are two rules which to all simple (i.e., non-compound) intervals:
- The number of any interval and the number of its inversion always add up to nine (four + five = nine, in the example just given).
- The inversion of a major interval is a minor interval (and vice versa); the inversion of a perfect interval is also perfect; the inversion of an augmented interval is a diminished interval (and vice versa); and the inversion of a double augmented interval is a double diminished interval (and vice versa).
- A full example: E♭ below and C above make a major sixth. By the two rules just given, C natural below and E flat above must make a minor third.
- For intervals identified by ratio, the inversion is determined by reversing the ratio and multiplying by 2. For example, the inversion of a 5:4 ratio is an 8:5 ratio.
- Intervals identified by integer can be simply subtracted from 12. However, since an interval class is the lower of the interval integer or its inversion, interval classes cannot be inverted.
Interval roots
Although intervals are usually designated in relation to their lower note,
David Cope and
Hindemith both suggest the concept of
interval root. To determine an interval's root, one locates its nearest approximation in the harmonic series. The root of a perfect fourth, then, is its
top note because it is an octave of the fundamental in the hypothetical harmonic series. The bottom note of every odd diatonically numbered intervals are the roots, as are the tops of all even numbered intervals. The root of a collection of intervals or a chord is thus determined by the interval root of its strongest interval.
As to its usefulness, Cope provides the example of the final tonic chord of some popular music being traditionally analyzable as a "submediant six-five chord" (
added sixth chords by popular terminology), or a first inversion seventh chord (possibly the dominant of the mediant V/iii). According the interval root of the strongest interval of the chord (in first inversion, CEGA), the perfect fifth (C–G), is the bottom C, the tonic.
Interval cycles
Interval cycles, "unfold a single recurrent interval in a series that closes with a return to the initial pitch class", and are notated by
George Perle using the letter "C", for cycle, with an interval class integer to distinguish the interval. Thus the diminished seventh chord would be C3 and the augmented triad would be C4. A superscript may be added to distinguish between transpositions, using 0–11 to indicate the lowest pitch class in the cycle. (Perle 1990, p.21)
Other intervals
There are also a number of intervals not found in the chromatic scale or labeled with a diatonic function which have names of their own. Many of these intervals describe small discrepancies between notes tuned according to the tuning systems used. Most of the following intervals may be described as
microtones.
- A Pythagorean comma is the difference between twelve justly tuned perfect fifths and seven octaves. It is expressed by the frequency ratio 531441:524288, and is equal to 23.46 cents.
- A syntonic comma is the difference between four justly tuned perfect fifths and two octaves plus a major third. It is expressed by the ratio 81:80, and is equal to 21.51 cents.
- A Septimal comma is 64:63, and is the difference between the Pythagorean or 3-limit "7th" and the "harmonic 7th".
- Diesis is generally used to mean the difference between three justly tuned major thirds and one octave. It is expressed by the ratio 128:125, and is equal to 41.06 cents. However, it has been used to mean other small intervals: see diesis for details.
- A diaschisma is the difference between three octaves and four justly tuned perfect fifths plus two justly tuned major thirds. It is expressed by the ratio 2048:2025, and is equal to about 19.5 cents.
- A schisma (also skhisma) is the difference between five octaves and eight justly tuned fifths plus one justly tuned major third. It is expressed by the ratio 32805:32768, and is equal to 1.95 cents. It is also the difference between the Pythagorean and syntonic commas.
- A schismic major third is a schisma different from a just major third, eight fifths down and five octaves up, F♭ in C.
- A quarter tone is half the width of a semitone, which is half the width of a whole tone. It is equal to 50 cents.
- A kleisma is six major thirds up, five fifths down and one octave up, or, sometimes, the septimal kleisma 225:224.
- A limma is the ratio 256:243, which is the semitone in Pythagorean tuning.
- A ditone is the pythagorean ratio 81:64, two 9:8 tones.
- Additionally, some cultures around the world have their own names for intervals found in their music. See: sargam, Bali
See
List of Musical Intervals for more.
See for popular musical fragments that feature common intervals
Generalizations and non-pitch uses
The term "interval" can also be generalized to other elements of music besides pitch.
David Lewin's
Generalized Musical Intervals and Transformations uses interval as a generic measure of distance in order to show musical transformations which can change, for instance, one rhythm into another, or one formal structure into another.
Notes
1.
^ Lindley, Mark/Campbell, Murray/Greated, Clive. "Interval",
Grove Music Online, ed. L. Macy (accessed
27 February 2007),
grovemusic.com (subscription access).
2.
^ Roeder, John. "Interval Class",
Grove Music Online, ed. L. Macy (accessed
27 February 2007),
grovemusic.com (subscription access).
3.
^ Kostka, Stephen; Payne, Dorothy.
Tonal Harmony. First Edition, 1984.
Sources
- Cope, David (1997). Techniques of the Contemporary Composer, p.40–41. New York, New York: Schirmer Books. ISBN 0-02-864737-8.
- Perle, George (1990). The Listening Composer. California: University of California Press. ISBN 0-520-06991-9.
- Lewin, David (1987). Generalized Musical Intervals and Transformations. New Haven: Yale University Press. Reprinted Oxford University Press, 2007. ISBN 978-0-19-531713-8.
External links
See also
This article or section is in need of attention from an expert on the subject.
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Pitch is the perceived fundamental frequency of a sound. While the actual fundamental frequency can be precisely determined through physical measurement, it may differ from the perceived pitch because of overtones, or partials, in the sound.
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note has two primary meanings: 1) a sign used in music to represent the relative duration and pitch of a sound; and 2) a pitched sound itself. Notes are the "atoms" of much Western music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis
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Distance may refer to:
- Distance in the mathematical and physical sense.
- Distance (band), a late-1980s rock supergroup featuring Bernard Edwards and Tony Thompson
..... Click the link for more information. harmony is the use and study of pitch simultaneity, and therefore chords, actual or implied, in music. The study of harmony may often refer to the study of harmonic progressions, the movement from one pitch simultaneity to another, and the structural principles that govern such
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melody, also tune, voice, or line, is a series of linear events or a succession, not a simultaneity as in a chord (see harmony). However, this succession must contain change of some kind and be perceived as a single entity (possibly Gestalt) to be called a
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In musical set theory, an interval class, or ic, is the shortest distance in pitch class space between two unordered pitch classes. For example, the interval class between pitch classes 4 and 9 is 5 because 9 - 4 = 5 is less than 4 - 9 = -5 ≡ 7.
..... Click the link for more information.
In music, a
pitch class is a set of all pitches that are a whole number of octaves apart, e.g. the pitch class C consists of the Cs in all octaves. Thus, using scientific pitch notation the pitch class "C" is the infinite set
- =
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Please help recruit one or [ improve this article] yourself. See the talk page for details.
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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In music, just intonation is any musical tuning in which the frequencies of notes are related by ratios of whole numbers. Any interval tuned in this way is called a just interval; in other words, the two notes are members of the same harmonic series.
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scale degree is the name of a particular note of a scale in relation to the tonic (the note of the scale that is considered the most important). The degrees of the traditional major and minor scales may be identified several ways:
..... Click the link for more information. In musical notation, the staff is a set of five horizontal lines and four spaces, on which note symbols are placed to indicate their relative pitch. The lines and spaces are numbered from bottom to top; the bottom line is the first line and the top line is the
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Perfect octave
Inverse unison
Name
Other names -
Abbreviation P8
Size
Semitones 12
Interval class 0
Just interval 2:1
Cents
Equal temperament 1200
Just intonation 1200 In music, an octave
..... Click the link for more information.
Perfect octave
Inverse unison
Name
Other names -
Abbreviation P8
Size
Semitones 12
Interval class 0
Just interval 2:1
Cents
Equal temperament 1200
Just intonation 1200 In music, an octave
..... Click the link for more information.
note has two primary meanings: 1) a sign used in music to represent the relative duration and pitch of a sound; and 2) a pitched sound itself. Notes are the "atoms" of much Western music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis
..... Click the link for more information.
Major may mean:
- Major, a military rank.
- An academic major, the primary focus of a Bachelor's degree, in the United States and some other countries.
- In music, major (in contrast to minor) is a type of scale, key, chord, or interval; see major and minor.
..... Click the link for more information. Not to be confused with myna or miner.
Minor means
not important. It may also may refer to:
Mathematics
- Minor (linear algebra), for a given matrix, its minor is the determinant of a certain smaller matrix
..... Click the link for more information. In music and music theory augmentation is the lengthening or widening of rhythms, melodies, intervals, chords. The opposite is diminution (as in "a diminished triad").
A melody or series of notes is augmented if the lengths of the notes are prolonged.
..... Click the link for more information.
Diminution, from Italian diminuimento, is a musical term used to mean different things in the context of melodies and intervals or chords.
A melody or series of notes is diminished if the lengths of the notes are shortened (this is opposed to
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UNiSON: Rebels of Rhythm & Dance (sometimes known as simply Unison) is a rhythm video game released for the PlayStation 2 in 2001 which featured unique controls and, at the time, beautiful graphics for its genre of game.
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perfect fourth
Inverse perfect fifth
Name
Other names diatessaron
Abbreviation P4
Size
Semitones 5
Interval class 5
Just interval 4:3
Cents
Equal temperament 500
Just intonation ~498.
..... Click the link for more information.
perfect fifth
Inverse perfect fourth
Name
Other names diapente
Abbreviation P5
Size
Semitones 7
Interval class 5
Just interval 3:2
Cents
Equal temperament 700
Just intonation 702 The
..... Click the link for more information.
Perfect octave
Inverse unison
Name
Other names -
Abbreviation P8
Size
Semitones 12
Interval class 0
Just interval 2:1
Cents
Equal temperament 1200
Just intonation 1200 In music, an octave
..... Click the link for more information.
In music and music theory augmentation is the lengthening or widening of rhythms, melodies, intervals, chords. The opposite is diminution (as in "a diminished triad").
A melody or series of notes is augmented if the lengths of the notes are prolonged.
..... Click the link for more information.
Diminution, from Italian diminuimento, is a musical term used to mean different things in the context of melodies and intervals or chords.
A melody or series of notes is diminished if the lengths of the notes are shortened (this is opposed to
..... Click the link for more information.
perfect fourth
Inverse perfect fifth
Name
Other names diatessaron
Abbreviation P4
Size
Semitones 5
Interval class 5
Just interval 4:3
Cents
Equal temperament 500
Just intonation ~498.
..... Click the link for more information.
perfect fifth
Inverse perfect fourth
Name
Other names diapente
Abbreviation P5
Size
Semitones 7
Interval class 5
Just interval 3:2
Cents
Equal temperament 700
Just intonation 702 The
..... Click the link for more information.
Perfect octave
Inverse unison
Name
Other names -
Abbreviation P8
Size
Semitones 12
Interval class 0
Just interval 2:1
Cents
Equal temperament 1200
Just intonation 1200 In music, an octave
..... Click the link for more information.
UNiSON: Rebels of Rhythm & Dance (sometimes known as simply Unison) is a rhythm video game released for the PlayStation 2 in 2001 which featured unique controls and, at the time, beautiful graphics for its genre of game.
..... Click the link for more information.