72edo: Difference between revisions

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Infobox precision, renew template for prime error table, and some other cleanups
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{{Infobox ET
{{Infobox ET
| Prime factorization = 2<sup>3</sup> × 3<sup>2</sup>
| Prime factorization = 2<sup>3</sup> × 3<sup>2</sup>
| Step size = 16.667¢
| Step size = 16.6667¢
| Fifth = 42\72 (700¢) (&rarr;[[12edo|7\12]])
| Fifth = 42\72 (700.0¢) ([[12edo|7\12]])
| Major 2nd = 12\72 (200¢)
| Major 2nd = 12\72 (200.0¢)
| Semitones = 6:6 (100¢ : 100¢)
| Semitones = 6:6 (100.0¢ : 100.0¢)
| Consistency = 17
| Consistency = 17
| Monotonicity = 29
| Monotonicity = 29
}}
}}
The '''72 equal divisions of the octave''' ('''72edo'''), or '''72-tone equal temperament''' ('''72tet''', '''72et''') when viewed from a [[regular temperament]] perspective, divides the [[octave]] into 72 steps or ''[[moria]]''. This produces a twelfth-tone tuning, with the whole tone measuring 200 cents, the same as in [[12edo]]. 72edo is also a superset of [[24edo]], a common and standard tuning of [[Arabic, Turkish, Persian|Arabic]] music, and has itself been used to tune Turkish music.
The '''72 equal divisions of the octave''' ('''72edo'''), or '''72-tone equal temperament''' ('''72tet''', '''72et''') when viewed from a [[regular temperament]] perspective, divides the [[octave]] into 72 steps or ''[[moria]]''. This produces a twelfth-tone tuning, with the whole tone measuring 200 cents, the same as in [[12edo]]. 72edo is also a superset of [[24edo]], a common and standard tuning of [[Arabic, Turkish, Persian|Arabic]] music, and has itself been used to tune Turkish music.


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== Theory ==
== Theory ==
{{Primes in edo|72|columns=11}}
72edo approximates [[11-limit]] [[just intonation]] exceptionally well, is [[consistent]] in the [[17-limit]], and is the ninth [[The Riemann Zeta Function and Tuning #Zeta EDO lists|Zeta integral tuning]]. The octave, fifth and fourth are the same size as they would be in 12edo, 72, 42 and 30 steps respectively, but the classic major third ([[5/4]]) measures 23 steps, not 24, and other [[5-limit]] major intervals are one step flat of 12edo while minor ones are one step sharp. The septimal minor seventh ([[7/4]]) is 58 steps, while the undecimal semiaugmented fourth ([[11/8]]) is 33.
72edo approximates [[11-limit]] [[just intonation]] exceptionally well, is [[consistent]] in the [[17-limit]], and is the ninth [[The Riemann Zeta Function and Tuning #Zeta EDO lists|Zeta integral tuning]]. The octave, fifth and fourth are the same size as they would be in 12edo, 72, 42 and 30 steps respectively, but the classic major third ([[5/4]]) measures 23 steps, not 24, and other [[5-limit]] major intervals are one step flat of 12edo while minor ones are one step sharp. The septimal minor seventh ([[7/4]]) is 58 steps, while the undecimal semiaugmented fourth ([[11/8]]) is 33.


72edo is an excellent tuning for the [[miracle]] temperament, especially the 11-limit version, and the related rank-3 temperament [[prodigy]], and is a good tuning for other temperaments and scales, including [[wizard]], [[harry]], [[catakleismic]], [[compton]], [[unidec]] and [[tritikleismic]].
72edo is an excellent tuning for the [[miracle]] temperament, especially the 11-limit version, and the related rank-3 temperament [[prodigy]], and is a good tuning for other temperaments and scales, including [[wizard]], [[harry]], [[catakleismic]], [[compton]], [[unidec]] and [[tritikleismic]].
=== Prime harmonics ===
{{Harmonics in equal|72|columns=11}}


== Intervals ==
== Intervals ==
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== Notations ==
== Notations ==
=== Sagittal ===
=== Sagittal ===
From the appendix to [[The Sagittal Songbook]] by [[Jacob Barton|Jacob A. Barton]], a diagram of how to notate 72-EDO in the Revo flavor of Sagittal:
From the appendix to [[The Sagittal Songbook]] by [[Jacob Barton|Jacob A. Barton]], a diagram of how to notate 72edo in the Revo flavor of Sagittal:


[[File:72edo Sagittal.png|800px]]
[[File:72edo Sagittal.png|800px]]
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|}
|}


72et is lower in relative error than any previous equal temperaments in the 7-, 11-, 13-, 17-, and 19-limit. The next ETs better in these subgroups are 99, 270, 224, 494, and 217, respectively.  
72et is lower in relative error than any previous equal temperaments in the 7-, 11-, 13-, 17-, and 19-limit. The next ETs doing better in these subgroups are 99, 270, 224, 494, and 217, respectively.  


=== Commas ===
=== Commas ===
Commas tempered out by 72edo include…
Commas tempered out by 72edo include…


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{| class="wikitable"
{| class="wikitable"
|-
|-
| | Harmonics in "Mode 8":
| Harmonics in "Mode 8":
| | 8
| 8
| |  
|  
| | 9
| 9
| |  
|  
| | 10
| 10
| |  
|  
| | 11
| 11
| |  
|  
| | 12
| 12
| |  
|  
| | 13
| 13
| |  
|  
| | 14
| 14
| |  
|  
| | 15
| 15
| |  
|  
| | 16
| 16
|-
|-
| | …as JI Ratio from 1/1:
| …as JI Ratio from 1/1:
| | 1/1
| 1/1
| |  
|  
| | 9/8
| 9/8
| |  
|  
| | 5/4
| 5/4
| |  
|  
| | 11/8
| 11/8
| |  
|  
| | 3/2
| 3/2
| |  
|  
| | 13/8
| 13/8
| |  
|  
| | 7/4
| 7/4
| |  
|  
| | 15/8
| 15/8
| |  
|  
| | 2/1
| 2/1
|-
|-
| | …in cents:
| …in cents:
| | 0
| 0
| |  
|  
| | 203.9
| 203.9
| |  
|  
| | 386.3
| 386.3
| |  
|  
| | 551.3
| 551.3
| |  
|  
| | 702.0
| 702.0
| |  
|  
| | 840.5
| 840.5
| |  
|  
| | 968.8
| 968.8
| |  
|  
| | 1088.3
| 1088.3
| |  
|  
| | 1200.0
| 1200.0
|-
|-
| | Nearest degree of 72edo:
| Nearest degree of 72edo:
| | 0
| 0
| |  
|  
| | 12
| 12
| |  
|  
| | 23
| 23
| |  
|  
| | 33
| 33
| |  
|  
| | 42
| 42
| |  
|  
| | 50
| 50
| |  
|  
| | 58
| 58
| |  
|  
| | 65
| 65
| |  
|  
| | 72
| 72
|-
|-
| | …in cents:
| …in cents:
| | 0
| 0
| |  
|  
| | 200.0
| 200.0
| |  
|  
| | 383.3
| 383.3
| |  
|  
| | 550.0
| 550.0
| |  
|  
| | 700.0
| 700.0
| |  
|  
| | 833.3
| 833.3
| |  
|  
| | 966.7
| 966.7
| |  
|  
| | 1083.3
| 1083.3
| |  
|  
| | 1200.0
| 1200.0
|-
|-
| | Steps as Freq. Ratio:
| Steps as Freq. Ratio:
| |  
|  
| | 9:8
| 9:8
| |  
|  
| | 10:9
| 10:9
| |  
|  
| | 11:10
| 11:10
| |  
|  
| | 12:11
| 12:11
| |  
|  
| | 13:12
| 13:12
| |  
|  
| | 14:13
| 14:13
| |  
|  
| | 15:14
| 15:14
| |  
|  
| | 16:15
| 16:15
| |  
|  
|-
|-
| | …in cents:
| …in cents:
| |  
|  
| | 203.9
| 203.9
| |  
|  
| | 182.4
| 182.4
| |  
|  
| | 165.0
| 165.0
| |  
|  
| | 150.6
| 150.6
| |  
|  
| | 138.6
| 138.6
| |  
|  
| | 128.3
| 128.3
| |  
|  
| | 119.4
| 119.4
| |  
|  
| | 111.7
| 111.7
| |  
|  
|-
|-
| | Nearest degree of 72edo:
| Nearest degree of 72edo:
| |  
|  
| | 12
| 12
| |  
|  
| | 11
| 11
| |  
|  
| | 10
| 10
| |  
|  
| | 9
| 9
| |  
|  
| | 8
| 8
| |  
|  
| | 8
| 8
| |  
|  
| | 7
| 7
| |  
|  
| | 7
| 7
| |  
|  
|-
|-
| | ...in cents:
| …in cents:
| |  
|  
| | 200.0
| 200.0
| |  
|  
| | 183.3
| 183.3
| |  
|  
| | 166.7
| 166.7
| |  
|  
| | 150.0
| 150.0
| |  
|  
| | 133.3
| 133.3
| |  
|  
| | 133.3
| 133.3
| |  
|  
| | 116.7
| 116.7
| |  
|  
| | 116.7
| 116.7
| |  
|  
|}
|}