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. | | Step size = 16.6667¢ | ||
| Fifth = 42\72 ( | | Fifth = 42\72 (700.0¢) (→ [[12edo|7\12]]) | ||
| Major 2nd = 12\72 ( | | Major 2nd = 12\72 (200.0¢) | ||
| Semitones = 6:6 ( | | 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 == | ||
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 | 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": | |||
| 8 | |||
| | |||
| 9 | |||
| | |||
| 10 | |||
| | |||
| 11 | |||
| | |||
| 12 | |||
| | |||
| 13 | |||
| | |||
| 14 | |||
| | |||
| 15 | |||
| | |||
| 16 | |||
|- | |- | ||
| …as JI Ratio from 1/1: | |||
| 1/1 | |||
| | |||
| 9/8 | |||
| | |||
| 5/4 | |||
| | |||
| 11/8 | |||
| | |||
| 3/2 | |||
| | |||
| 13/8 | |||
| | |||
| 7/4 | |||
| | |||
| 15/8 | |||
| | |||
| 2/1 | |||
|- | |- | ||
| …in cents: | |||
| 0 | |||
| | |||
| 203.9 | |||
| | |||
| 386.3 | |||
| | |||
| 551.3 | |||
| | |||
| 702.0 | |||
| | |||
| 840.5 | |||
| | |||
| 968.8 | |||
| | |||
| 1088.3 | |||
| | |||
| 1200.0 | |||
|- | |- | ||
| Nearest degree of 72edo: | |||
| 0 | |||
| | |||
| 12 | |||
| | |||
| 23 | |||
| | |||
| 33 | |||
| | |||
| 42 | |||
| | |||
| 50 | |||
| | |||
| 58 | |||
| | |||
| 65 | |||
| | |||
| 72 | |||
|- | |- | ||
| …in cents: | |||
| 0 | |||
| | |||
| 200.0 | |||
| | |||
| 383.3 | |||
| | |||
| 550.0 | |||
| | |||
| 700.0 | |||
| | |||
| 833.3 | |||
| | |||
| 966.7 | |||
| | |||
| 1083.3 | |||
| | |||
| 1200.0 | |||
|- | |- | ||
| Steps as Freq. Ratio: | |||
| | |||
| 9:8 | |||
| | |||
| 10:9 | |||
| | |||
| 11:10 | |||
| | |||
| 12:11 | |||
| | |||
| 13:12 | |||
| | |||
| 14:13 | |||
| | |||
| 15:14 | |||
| | |||
| 16:15 | |||
| | |||
|- | |- | ||
| …in cents: | |||
| | |||
| 203.9 | |||
| | |||
| 182.4 | |||
| | |||
| 165.0 | |||
| | |||
| 150.6 | |||
| | |||
| 138.6 | |||
| | |||
| 128.3 | |||
| | |||
| 119.4 | |||
| | |||
| 111.7 | |||
| | |||
|- | |- | ||
| Nearest degree of 72edo: | |||
| | |||
| 12 | |||
| | |||
| 11 | |||
| | |||
| 10 | |||
| | |||
| 9 | |||
| | |||
| 8 | |||
| | |||
| 8 | |||
| | |||
| 7 | |||
| | |||
| 7 | |||
| | |||
|- | |- | ||
| | | …in cents: | ||
| | |||
| 200.0 | |||
| | |||
| 183.3 | |||
| | |||
| 166.7 | |||
| | |||
| 150.0 | |||
| | |||
| 133.3 | |||
| | |||
| 133.3 | |||
| | |||
| 116.7 | |||
| | |||
| 116.7 | |||
| | |||
|} | |} | ||