Английская Википедия:12 equal temperament

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Шаблон:Short description

Файл:Chromatische toonladder.png
12-tone equal temperament chromatic scale on C, one full octave ascending, notated only with sharps. Шаблон:Audio

12 equal temperament (12-ET)Шаблон:Efn is the musical system that divides the octave into 12 parts, all of which are equally tempered (equally spaced) on a logarithmic scale, with a ratio equal to the 12th root of 2 (Шаблон:Radic ≈ 1.05946). That resulting smallest interval, Шаблон:Frac the width of an octave, is called a semitone or half step.

Twelve-tone equal temperament is the most widespread system in music today. It has been the predominant tuning system of Western music, starting with classical music, since the 18th century, and Europe almost exclusively used approximations of it for millennia before that.Шаблон:Citation needed It has also been used in other cultures.

In modern times, 12-ET is usually tuned relative to a standard pitch of 440 Hz, called A440, meaning one note, A, is tuned to 440 hertz and all other notes are defined as some multiple of semitones apart from it, either higher or lower in frequency. The standard pitch has not always been 440 Hz. It has varied and generally risen over the past few hundred years.Шаблон:Sfn

History

The two figures frequently credited with the achievement of exact calculation of twelve-tone equal temperament are Zhu Zaiyu (also romanized as Chu-Tsaiyu. Chinese: Шаблон:Lang) in 1584 and Simon Stevin in 1585. According to Fritz A. Kuttner, a critic of the theory,Шаблон:Sfn it is known that "Chu-Tsaiyu presented a highly precise, simple and ingenious method for arithmetic calculation of equal temperament mono-chords in 1584" and that "Simon Stevin offered a mathematical definition of equal temperament plus a somewhat less precise computation of the corresponding numerical values in 1585 or later." The developments occurred independently.Шаблон:Sfn

Kenneth Robinson attributes the invention of equal temperament to Zhu ZaiyuШаблон:Sfn and provides textual quotations as evidence.Шаблон:Sfn Zhu Zaiyu is quoted as saying that, in a text dating from 1584, "I have founded a new system. I establish one foot as the number from which the others are to be extracted, and using proportions I extract them. Altogether one has to find the exact figures for the pitch-pipers in twelve operations."Шаблон:Sfn Kuttner disagrees and remarks that his claim "cannot be considered correct without major qualifications."Шаблон:Sfn Kuttner proposes that neither Zhu Zaiyu or Simon Stevin achieved equal temperament and that neither of the two should be treated as inventors.Шаблон:Sfn

China

Early history

A complete set of bronze chime bells, among many musical instruments found in the tomb of the Marquis Yi of Zeng (early Warring States, Шаблон:Circa in the Chinese Bronze Age), covers five full 7-note octaves in the key of C Major, including 12 note semi-tones in the middle of the range.Шаблон:Sfn

An approximation for equal temperament was described by Шаблон:Ill, a mathematician of the Southern and Northern Dynasties who lived from 370 to 447.[1] He came out with the earliest recorded approximate numerical sequence in relation to equal temperament in history: 900 849 802 758 715 677 638 601 570 536 509.5 479 450.Шаблон:Sfn

Zhu Zaiyu

Файл:乐律全书全-2297.jpg
Prince Zhu Zaiyu constructed 12 string equal temperament tuning instrument, front and back view

Zhu Zaiyu (Шаблон:Lang), a prince of the Ming court, spent thirty years on research based on the equal temperament idea originally postulated by his father. He described his new pitch theory in his Fusion of Music and Calendar Шаблон:Lang published in 1580. This was followed by the publication of a detailed account of the new theory of the equal temperament with a precise numerical specification for 12-ET in his 5,000-page work Complete Compendium of Music and Pitch (Yuelü quan shu Шаблон:Lang) in 1584.Шаблон:Sfn An extended account is also given by Joseph Needham.Шаблон:Sfn Zhu obtained his result mathematically by dividing the length of string and pipe successively by Шаблон:Radic ≈ 1.059463, and for pipe length by Шаблон:Radic,Шаблон:Sfn such that after twelve divisions (an octave) the length was divided by a factor of 2:

<math display="block">\left( \sqrt[12]{2} \right)^{12} = 2</math>

Similarly, after 84 divisions (7 octaves) the length was divided by a factor of 128:

<math display="block">\left( \sqrt[12]{2} \right)^{84} = 2^7 = 128</math>

Zhu Zaiyu has been credited as the first person to solve the equal temperament problem mathematically.Шаблон:Sfn At least one researcher has proposed that Matteo Ricci, a Jesuit in China recorded this work in his personal journalШаблон:SfnШаблон:Sfn and may have transmitted the work back to Europe. (Standard resources on the topic make no mention of any such transfer.Шаблон:Sfn) In 1620, Zhu's work was referenced by a European mathematician.Шаблон:WhoШаблон:Sfn Murray Barbour said, "The first known appearance in print of the correct figures for equal temperament was in China, where Prince Tsaiyü's brilliant solution remains an enigma."Шаблон:Sfn The 19th-century German physicist Hermann von Helmholtz wrote in On the Sensations of Tone that a Chinese prince (see below) introduced a scale of seven notes, and that the division of the octave into twelve semitones was discovered in China.Шаблон:Sfn

Файл:乐律全书全-1154.jpg
Zhu Zaiyu's equal temperament pitch pipes

Zhu Zaiyu illustrated his equal temperament theory by the construction of a set of 36 bamboo tuning pipes ranging in 3 octaves, with instructions of the type of bamboo, color of paint, and detailed specification on their length and inner and outer diameters. He also constructed a 12-string tuning instrument, with a set of tuning pitch pipes hidden inside its bottom cavity. In 1890, Victor-Charles Mahillon, curator of the Conservatoire museum in Brussels, duplicated a set of pitch pipes according to Zhu Zaiyu's specification. He said that the Chinese theory of tones knew more about the length of pitch pipes than its Western counterpart, and that the set of pipes duplicated according to the Zaiyu data proved the accuracy of this theory.

Europe

Файл:De Spiegheling der signconst.jpg
Simon Stevin's Шаблон:Lang Шаблон:Circa.

Early history

One of the earliest discussions of equal temperament occurs in the writing of Aristoxenus in the 4th century BC.Шаблон:Sfn

Vincenzo Galilei (father of Galileo Galilei) was one of the first practical advocates of twelve-tone equal temperament. He composed a set of dance suites on each of the 12 notes of the chromatic scale in all the "transposition keys", and published also, in his 1584 "Fronimo", 24 + 1 ricercars.Шаблон:Sfn He used the 18:17 ratio for fretting the lute (although some adjustment was necessary for pure octaves).Шаблон:Sfn

Galilei's countryman and fellow lutenist Giacomo Gorzanis had written music based on equal temperament by 1567.Шаблон:Sfn Gorzanis was not the only lutenist to explore all modes or keys: Francesco Spinacino wrote a Шаблон:Lang (Ricercar in all the Tones) as early as 1507.[2] In the 17th century lutenist-composer John Wilson wrote a set of 30 preludes including 24 in all the major/minor keys.Шаблон:SfnШаблон:Sfn Henricus Grammateus drew a close approximation to equal temperament in 1518. The first tuning rules in equal temperament were given by Giovani Maria Lanfranco in his "Scintille de musica".[3] Zarlino in his polemic with Galilei initially opposed equal temperament but eventually conceded to it in relation to the lute in his Шаблон:Lang in 1588.

Simon Stevin

The first mention of equal temperament related to the twelfth root of two in the West appeared in Simon Stevin's manuscript Шаблон:Lang (c. 1605), published posthumously nearly three centuries later in 1884.Шаблон:Sfn However, due to insufficient accuracy of his calculation, many of the chord length numbers he obtained were off by one or two units from the correct values.Шаблон:Sfn As a result, the frequency ratios of Simon Stevin's chords has no unified ratio, but one ratio per tone, which is claimed by Gene Cho as incorrect.Шаблон:Sfn

The following were Simon Stevin's chord length from Шаблон:Lang:Шаблон:Sfn

Tone Chord 10000 from Simon Stevin Ratio Corrected chord
semitone 9438 1.0595465 9438.7
whole tone 8909 1.0593781
tone and a half 8404 1.0600904 8409
ditone 7936 1.0594758 7937
ditone and a half 7491 1.0594046 7491.5
tritone 7071 1.0593975 7071.1
tritone and a half 6674 1.0594845 6674.2
four-tone 6298 1.0597014 6299
four-tone and a half 5944 1.0595558 5946
five-tone 5611 1.0593477 5612.3
five-tone and a half 5296 1.0594788 5297.2
full tone 1.0592000

A generation later, French mathematician Marin Mersenne presented several equal tempered chord lengths obtained by Jean Beaugrand, Ismael Bouillaud, and Jean Galle.Шаблон:Sfn

In 1630 Johann Faulhaber published a 100-cent monochord table, which contained several errors due to his use of logarithmic tables. He did not explain how he obtained his results.Шаблон:Sfn

Baroque era

From 1450 to about 1800, plucked instrument players (lutenists and guitarists) generally favored equal temperament,[4] and the Brossard lute manuscript compiled in the last quarter of the 17th century contains a series of 18 preludes attributed to Bocquet written in all keys, including the last prelude, entitled Шаблон:Lang, which enharmonically modulates through all keys.[5]Шаблон:Huh? Angelo Michele Bartolotti published a series of passacaglias in all keys, with connecting enharmonically modulating passages. Among the 17th-century keyboard composers Girolamo Frescobaldi advocated equal temperament. Some theorists, such as Giuseppe Tartini, were opposed to the adoption of equal temperament; they felt that degrading the purity of each chord degraded the aesthetic appeal of music, although Andreas Werckmeister emphatically advocated equal temperament in his 1707 treatise published posthumously.[6]

Twelve-tone equal temperament took hold for a variety of reasons. It was a convenient fit for the existing keyboard design, and permitted total harmonic freedom with the burden of moderate impurity in every interval, particularly imperfect consonances. This allowed greater expression through enharmonic modulation, which became extremely important in the 18th century in music of such composers as Francesco Geminiani, Wilhelm Friedemann Bach, Carl Philipp Emmanuel Bach, and Johann Gottfried Müthel.Шаблон:Citation needed Twelve-tone equal temperament did have some disadvantages, such as imperfect thirds, but as Europe switched to equal temperament, it changed the music that it wrote in order to accommodate the system and minimize dissonance.Шаблон:Efn

The progress of equal temperament from the mid-18th century on is described with detail in quite a few modern scholarly publications: It was already the temperament of choice during the Classical era (second half of the 18th century),Шаблон:Citation needed and it became standard during the Early Romantic era (first decade of the 19th century),Шаблон:Citation needed except for organs that switched to it more gradually, completing only in the second decade of the 19th century. (In England, some cathedral organists and choirmasters held out against it even after that date; Samuel Sebastian Wesley, for instance, opposed it all along. He died in 1876.)Шаблон:Citation needed

A precise equal temperament is possible using the 17th century Sabbatini method of splitting the octave first into three tempered major thirds.Шаблон:Sfn This was also proposed by several writers during the Classical era. Tuning without beat rates but employing several checks, achieving virtually modern accuracy, was already done in the first decades of the 19th century.Шаблон:Sfn Using beat rates, first proposed in 1749, became common after their diffusion by Helmholtz and Ellis in the second half of the 19th century.Шаблон:Sfn The ultimate precision was available with 2 decimal tables published by White in 1917.[7]

It is in the environment of equal temperament that the new styles of symmetrical tonality and polytonality, atonal music such as that written with the twelve tone technique or serialism, and jazz (at least its piano component) developed and flourished.

Comparison of historical approximations of the semitone

Year Name RatioШаблон:Sfn Cents
400 He Chengtian 1.060070671 101.0
1580 Vincenzo Galilei 18:17 [1.058823529] 99.0
1581 Zhu Zaiyu 1.059463094 100.0
1585 Simon Stevin 1.059546514 100.1
1630 Marin Mersenne 1.059322034 99.8
1630 Johann Faulhaber 1.059490385 100.0

Mathematical properties

Файл:Monochord ET.png
One octave of 12-ET on a monochord

In twelve-tone equal temperament, which divides the octave into 12 equal parts, the width of a semitone, i.e. the frequency ratio of the interval between two adjacent notes, is the twelfth root of two:

<math display="block">\sqrt[12]{2} = 2^{\frac{1}{12}} \approx 1.059463</math>

This interval is divided into 100 cents.

Calculating absolute frequencies

Шаблон:See also To find the frequency, Шаблон:Math, of a note in 12-ET, the following definition may be used:

<math display="block">P_{n} = P_{a}\left( \sqrt[12]{2} \right)^{(n-a)}</math>

In this formula Шаблон:Math refers to the pitch, or frequency (usually in hertz), you are trying to find. Шаблон:Math refers to the frequency of a reference pitch. Шаблон:Mvar and Шаблон:Mvar refer to numbers assigned to the desired pitch and the reference pitch, respectively. These two numbers are from a list of consecutive integers assigned to consecutive semitones. For example, A4 (the reference pitch) is the 49th key from the left end of a piano (tuned to 440 Hz), and C4 (middle C), and F#4 are the 40th and 46th key respectively. These numbers can be used to find the frequency of C4 and F#4:

<math display="block">\begin{alignat}{3} P_{40} &= 440\left( \sqrt[12]{2} \right)^{(40-49)} &&\approx 261.626 \ \mathrm{Hz} \\ P_{46} &= 440\left(\sqrt[12]{2} \right)^{(46-49)} &&\approx 369.994 \ \mathrm{Hz} \end{alignat}</math>

Just intervals

Файл:12ed2-7Limit.svg
7-Limit just intervals approximated in 12-ET

The intervals of 12-ET closely approximate some intervals in just intonation.Шаблон:Sfn

By limit

12 ET is very accurate in the 3 limit, but as one increases prime limits to 11, it gradually gets worse by about a sixth of a semitone each time. Its eleventh and thirteenth harmonics are extremely inaccurate. 12 ET's seventeenth and nineteenth harmonics are almost as accurate as its third harmonic, but by this point, the prime limit has gotten too high to sound consonant to most people.Шаблон:Citation needed

3 limit

Шаблон:See also 12 ET has a very good approximation of the perfect fifth (Шаблон:Sfrac) and its inversion, the perfect fourth (Шаблон:Sfrac), especially for the division of the octave into a relatively small number of tones. Specifically, a just perfect fifth is only one fifty-first of a semitone sharper than the equally-tempered approximation. Because the major tone (Шаблон:Sfrac) is simply two perfect fifths minus an octave, and its inversion, the Pythagorean minor seventh (Шаблон:Sfrac), is simply two perfect fourths combined, they, for the most part, retain the accuracy of their predecessors; the error is doubled, but it remains small – so small, in fact, that humans cannot perceive it. One can continue to use fractions with higher powers of three, the next two being Шаблон:Sfrac and Шаблон:Sfrac, but as the terms of the fractions grow larger, they become less pleasing to the ear.Шаблон:Citation needed

5 limit

Шаблон:See also 12 ET's approximation of the fifth harmonic (Шаблон:Sfrac) is approximately one-seventh of a semitone off. Because intervals that are less than a quarter of a scale step off still sound in tune, other five-limit intervals in 12 ET, such as Шаблон:Sfrac and Шаблон:Sfrac, have similarly sized errors. The major triad, therefore, sounds in tune as its frequency ratio is approximately 4:5:6, further, merged with its first inversion, and two sub-octave tonics, it is 1:2:3:4:5:6, all six lowest natural harmonics of the bass tone.Шаблон:Citation needed

7 limit

Шаблон:See also 12 ET's approximation of the seventh harmonic (Шаблон:Sfrac) is about one-third of a semitone off. Because the error is greater than a quarter of a semitone, seven-limit intervals in 12 ET tend to sound out of tune. In the tritone fractions Шаблон:Sfrac and Шаблон:Sfrac, the errors of the fifth and seventh harmonics partially cancel each other out so that the just fractions are within a quarter of a semitone of their equally-tempered equivalents, but the tritone still sounds dissonant to most people.Шаблон:Citation needed

11 and 13 limits

The eleventh harmonic (Шаблон:Sfrac) is about 550 cents, meaning that it falls almost exactly halfway between the nearest two equally-tempered intervals in 12 ET and therefore is not approximated by either. In fact, Шаблон:Sfrac is almost as far from any equally-tempered approximation as possible in 12 ET. The thirteenth harmonic (Шаблон:Sfrac), at about two-fifths of a semitone sharper than a minor sixth, is almost as inaccurate. Although this means that the fraction Шаблон:Sfrac (and also its inversion, Шаблон:Sfrac) is accurately approximated (specifically, by three semitones), since the errors of the eleventh and thirteenth harmonics mostly cancel out, most people who are not used to quarter tones are not used to the eleventh and thirteenth harmonics, so this fraction would not sound consonant to most people. Similarly, the error of the eleventh or thirteenth harmonic could be mostly canceled out by the error of the seventh harmonic, but for the same reason as before, most people would not find the resulting fractions consonant.Шаблон:Citation needed

17 and 19 limits

The seventeenth harmonic (Шаблон:Sfrac) is only about 5 cents sharper than one semitone in 12 ET. It can be combined with 12 ET's approximation of the third harmonic in order to yield Шаблон:Sfrac, which is, as the next Pell approximation after Шаблон:Sfrac, only about three cents away from the equally-tempered tritone (the square root of two), and Шаблон:Sfrac, which is only one cent away from 12 ET's major seventh. The nineteenth harmonic is only about 2.5 cents flatter than three of 12 ET's semitones, so it can likewise be combined with the third harmonic to yield Шаблон:Sfrac, which is about 4.5 cents flatter than an equally-tempered minor sixth, and Шаблон:Sfrac, which is about 6.5 cents flatter than a semitone. However, because 17 and 19 are rather large for consonant ratios and most people are unfamiliar with 17 limit and 19 limit intervals, 17 limit and 19 limit intervals are not useful for most purposes, so they can likely not be judged as playing a part in any consonances of 12 ET.Шаблон:Citation needed

Table

In the following table the sizes of various just intervals are compared against their equal-tempered counterparts, given as a ratio as well as cents. Differences of less than six cents cannot be noticed by most people, and intervals that are more than a quarter of a step; which in this case is 25 cents, off sound out of tune.Шаблон:Citation needed

Number of steps Note going up from C Exact value in 12-ET Decimal value in 12-ET Equally-tempered audio Cents Just intonation interval name Just intonation interval fraction Justly-intoned audio Cents in just intonation Difference
0 C 2Шаблон:Sup = 1 1 Шаблон:Audio 0 Unison Шаблон:Frac = 1 Шаблон:Audio 0 0
1 [[C♯ (musical note)|CШаблон:Music]] or [[D♭ (musical note)|DШаблон:Music]] 2Шаблон:Sup = Шаблон:Radic 1.05946... Шаблон:Audio 100 Septimal third tone Шаблон:Frac = 1.03703... Шаблон:Audio 62.96 -37.04
Just chromatic semitone Шаблон:Frac = 1.04166... Шаблон:Audio 70.67 -29.33
Undecimal semitone Шаблон:Frac = 1.04761... Шаблон:Audio 80.54 -19.46
Septimal chromatic semitone Шаблон:Frac = 1.05 Шаблон:Audio 84.47 -15.53
Novendecimal chromatic semitone Шаблон:Frac = 1.05263... Шаблон:Audio 88.80 -11.20
Pythagorean diatonic semitone Шаблон:Frac = 1.05349... Шаблон:Audio 90.22 -9.78
Larger chromatic semitone Шаблон:Frac = 1.05468... Шаблон:Audio 92.18 -7.82
Novendecimal diatonic semitone Шаблон:Frac = 1.05555... Шаблон:Audio 93.60 -6.40
Septadecimal chromatic semitone Шаблон:Frac = 1.05882... Шаблон:Audio 98.95 -1.05
Seventeenth harmonic Шаблон:Frac = 1.0625... Шаблон:Audio 104.96 +4.96
Just diatonic semitone Шаблон:Frac = 1.06666... Шаблон:Audio 111.73 +11.73
Pythagorean chromatic semitone Шаблон:Frac = 1.06787... Шаблон:Audio 113.69 +13.69
Septimal diatonic semitone Шаблон:Frac = 1.07142... Шаблон:Audio 119.44 +19.44
Lesser tridecimal 2/3-tone Шаблон:Frac = 1.07692... Шаблон:Audio 128.30 +28.30
Major diatonic semitone Шаблон:Frac = 1.08 Шаблон:Audio 133.24 +33.24
2 D 2Шаблон:Sup = Шаблон:Radic 1.12246... Шаблон:Audio 200 Pythagorean diminished third Шаблон:Frac = 1.10985... Шаблон:Audio 180.45 -19.55
Minor tone Шаблон:Frac = 1.11111... Шаблон:Audio 182.40 -17.60
Major tone Шаблон:Frac = 1.125 Шаблон:Audio 203.91 +3.91
Septimal whole tone Шаблон:Frac = 1.14285... Шаблон:Audio 231.17 +31.17
3 [[D♯ (musical note)|DШаблон:Music]] or [[E♭ (musical note)|EШаблон:Music]] 2Шаблон:Sup = Шаблон:Radic 1.18920... Шаблон:Audio 300 Septimal minor third Шаблон:Frac = 1.16666... Шаблон:Audio 266.87 -33.13
Tridecimal minor third Шаблон:Frac = 1.18181... Шаблон:Audio 289.21 -10.79
Pythagorean minor third Шаблон:Frac = 1.18518... Шаблон:Audio 294.13 -5.87
Nineteenth harmonic Шаблон:Frac = 1.1875 Шаблон:Audio 297.51 -2.49
Just minor third Шаблон:Frac = 1.2 Шаблон:Audio 315.64 +15.64
Pythagorean augmented second Шаблон:Frac = 1.20135... Шаблон:Audio 317.60 +17.60
4 E 2Шаблон:Sup = Шаблон:Radic 1.25992... Шаблон:Audio 400 Pythagorean diminished fourth Шаблон:Frac = 1.24859... Шаблон:Audio 384.36 -15.64
Just major third Шаблон:Frac = 1.25 Шаблон:Audio 386.31 -13.69
Pythagorean major third Шаблон:Frac = 1.265625 Шаблон:Audio 407.82 +7.82
Undecimal major third Шаблон:Frac = 1.27272... Шаблон:Audio 417.51 +17.51
Septimal major third Шаблон:Frac = 1.28571... Шаблон:Audio 435.08 +35.08
5 F 2Шаблон:Sup = Шаблон:Radic 1.33484... Шаблон:Audio 500 Just perfect fourth Шаблон:Frac = 1.33333... Шаблон:Audio 498.04 -1.96
Pythagorean augmented third Шаблон:Frac = 1.35152... Шаблон:Audio 521.51 +21.51
6 [[F♯ (musical note)|FШаблон:Music]] or [[G♭ (musical note)|GШаблон:Music]] 2Шаблон:Sup = Шаблон:Sqrt 1.41421... Шаблон:Audio 600 Classic augmented fourth Шаблон:Frac = 1.38888... Шаблон:Audio 568.72 -31.28
Huygens' tritone Шаблон:Frac = 1.4 Шаблон:Audio 582.51 -17.49
Pythagorean diminished fifth Шаблон:Frac = 1.40466... Шаблон:Audio 588.27 -11.73
Just augmented fourth Шаблон:Frac = 1.40625 Шаблон:Audio 590.22 -9.78
Just diminished fifth Шаблон:Frac = 1.42222... Шаблон:Audio 609.78 +9.78
Pythagorean augmented fourth Шаблон:Frac = 1.42382... Шаблон:Audio 611.73 +11.73
Euler's tritone Шаблон:Frac = 1.42857... Шаблон:Audio 617.49 +17.49
Classic diminished fifth Шаблон:Frac = 1.44 Шаблон:Audio 631.28 +31.28
7 G 2Шаблон:Sup = Шаблон:Radic 1.49830... Шаблон:Audio 700 Pythagorean diminished sixth Шаблон:Frac = 1.47981... Шаблон:Audio 678.49 -21.51
Just perfect fifth Шаблон:Frac = 1.5 Шаблон:Audio 701.96 +1.96
8 [[G♯ (musical note)|GШаблон:Music]] or [[A♭ (musical note)|AШаблон:Music]] 2Шаблон:Sup = Шаблон:Radic 1.58740... Шаблон:Audio 800 Septimal minor sixth Шаблон:Frac = 1.55555... Шаблон:Audio 764.92 -35.08
Undecimal minor sixth Шаблон:Frac = 1.57142... Шаблон:Audio 782.49 -17.51
Pythagorean minor sixth Шаблон:Frac = 1.58024... Шаблон:Audio 792.18 -7.82
Just minor sixth Шаблон:Frac = 1.6 Шаблон:Audio 813.69 +13.69
Pythagorean augmented fifth Шаблон:Frac = 1.60180... Шаблон:Audio 815.64 +15.64
9 A 2Шаблон:Sup = Шаблон:Radic 1.68179... Шаблон:Audio 900 Pythagorean diminished seventh Шаблон:Frac = 1.66478... Шаблон:Audio 882.40 -17.60
Just major sixth Шаблон:Frac = 1.66666... Шаблон:Audio 884.36 -15.64
Nineteenth subharmonic Шаблон:Frac = 1.68421... Шаблон:Audio 902.49 +2.49
Pythagorean major sixth Шаблон:Frac = 1.6875 Шаблон:Audio 905.87 +5.87
Septimal major sixth Шаблон:Frac = 1.71428... Шаблон:Audio 933.13 +33.13
10 [[A♯ (musical note)|AШаблон:Music]] or [[B♭ (musical note)|BШаблон:Music]] 2Шаблон:Sup = Шаблон:Radic 1.78179... Шаблон:Audio 1000 Harmonic seventh Шаблон:Frac = 1.75 Шаблон:Audio 968.83 -31.17
Pythagorean minor seventh Шаблон:Frac = 1.77777... Шаблон:Audio 996.09 -3.91
Large minor seventh Шаблон:Frac = 1.8 Шаблон:Audio 1017.60 +17.60
Pythagorean augmented sixth Шаблон:Frac = 1.80203... Шаблон:Audio 1019.55 +19.55
11 B 2Шаблон:Sup = Шаблон:Radic 1.88774... Шаблон:Audio 1100 Tridecimal neutral seventh Шаблон:Frac = 1.85714... Шаблон:Audio 1071.70 -28.30
Pythagorean diminished octave Шаблон:Frac = 1.87288... Шаблон:Audio 1086.31 -13.69
Just major seventh Шаблон:Frac = 1.875 Шаблон:Audio 1088.27 -11.73
Seventeenth subharmonic Шаблон:Frac = 1.88235... Шаблон:Audio 1095.04 -4.96
Pythagorean major seventh Шаблон:Frac = 1.89843... Шаблон:Audio 1109.78 +9.78
Septimal major seventh Шаблон:Frac = 1.92857... Шаблон:Audio 1137.04 +37.04
12 C 2Шаблон:Sup = 2 2 Шаблон:Audio 1200 Octave Шаблон:Frac = 2 Шаблон:Audio 1200.00 0

Commas

12-ET tempers out several commas, meaning that there are several fractions close to Шаблон:Sfrac that are treated as Шаблон:Sfrac by 12-ET due to its mapping of different fractions to the same equally-tempered interval. For example, Шаблон:Sfrac (Шаблон:Sfrac) and Шаблон:Sfrac (Шаблон:Sfrac) are each mapped to the tritone, so they are treated as nominally the same interval; therefore, their quotient, Шаблон:Sfrac (Шаблон:Sfrac) is mapped to/treated as unison. This is the Pythagorean comma, and it is 12-ET's only 3-limit comma. However, as one increases the prime limit and includes more intervals, the number of commas increases. 12-ET's most important five-limit comma is Шаблон:Sfrac (Шаблон:Sfrac), which is known as the syntonic comma and is the factor between Pythagorean thirds and sixths and their just counterparts. 12-ET's other 5-limit commas include:

One of the 7-limit commas that 12-ET tempers out is the septimal kleisma, which is equal to Шаблон:Sfrac, or Шаблон:Nowrap 12-ET's other 7-limit commas include:

Similar tuning systems

Historically, multiple tuning systems have been used that can be seen as slight variations of 12-TEDO, with twelve notes per octave but with some variation among interval sizes so that the notes are not quite equally-spaced. One example of this a three-limit scale where equally-tempered perfect fifths of 700 cents are replaced with justly-intoned perfect fifths of 701.955 cents. Because the two intervals differ by less than 2 cents, or Шаблон:Frac of an octave, the two scales are very similar. In fact, the Chinese developed 3-limit just intonation at least a century before He Chengtian created the sequence of 12-TEDO.Шаблон:Sfn Likewise, Pythagorean tuning, which was developed by ancient Greeks, was the predominant system in Europe until during the Renaissance, when Europeans realized that dissonant intervals such as Шаблон:FracШаблон:Sfn could be made more consonant by tempering them to simpler ratios like Шаблон:Frac, resulting in Europe developing a series of meantone temperaments that slightly modified the interval sizes but could still be viewed as an approximate of 12-TEDO. Due to meantone temperaments' tendency to concentrate error onto one enharmonic perfect fifth, making it very dissonant, European music theorists, such as Andreas Werckmeister, Johann Philipp Kirnberger, Francesco Antonio Vallotti, and Thomas Young, created various well temperaments with the goal of dividing up the commas in order to reduce the dissonance of the worst-affected intervals. Werckmeister and Kirnberger were each dissatisfied with his first temperament and therefore created multiple temperaments, the latter temperaments more closely approximating equal temperament than the former temperaments. Likewise, Europe as a whole gradually transitioned from meantone and well temperaments to 12-TEDO, the system that it still uses today.

Subsets

Шаблон:See also While some types of music, such as serialism, use all twelve notes of 12-TEDO, most music only uses notes from a particular subset of 12-TEDO known as a scale. Many different types of scales exist.

The most popular type of scale in 12-TEDO is meantone. Meantone refers to any scale where all of its notes are consecutive on the circle of fifths. Meantone scales of different sizes exist, and some meantone scales used include five-note meantone, seven-note meantone, and nine-note meantone. Meantone is present in the design of Western instruments. For example, the keys of a piano and its predecessors are structured so that the white keys form a seven-note meantone scale and the black keys form a five-note meantone scale. Another example is that guitars and other string instruments with at least five strings are typically tuned so that their open strings form a five-note meantone scale.

Other scales used in 12-TEDO include the ascending melodic minor scale, the harmonic minor, the harmonic major, the diminished scale, and the in scale.

See also

References

Footnotes

Шаблон:Notelist

Citations

Шаблон:Reflist

Sources

Шаблон:Refbegin

Шаблон:Refend

Further reading

Шаблон:Refbegin

Шаблон:Refend

External links

Шаблон:Musical tuning

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  4. Lindley, Mark. Lutes, Viols, Temperaments. Шаблон:ISBN
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  6. Andreas Werckmeister (1707), Шаблон:Lang
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