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| {{Infobox ET}} | | {{Infobox ET}} |
| The '''217 equal divisions of the octave''' ('''217edo'''), or the '''217(-tone) equal temperament''' ('''217tet''', '''217et''') when viewed from a [[regular temperament]] perspective, is the [[EDO|equal division of the octave]] into 217 parts of about 5.53 [[cent]]s each.
| | {{EDO intro|217}} |
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| == Theory == | | == Theory == |
| 217edo is a strong [[19-limit]] system, the smallest uniquely [[consistent]] in the [[19-odd-limit]] and consistent to the [[21-odd-limit]]. It shares the same 5th and 7th [[Harmonic series|harmonics]] with [[31edo]] (217 = 7 × 31), as well as the [[11/9]] interval (supporting the [[31-comma temperaments #Birds|birds temperament]]). However, compared to 31edo, its [[patent val]] differ on the mappings for 3, 11, 13, 17 and 19 – in fact, this edo has a very accurate 13th harmonic, as well as the [[19/15]] interval. | | 217edo is a strong [[19-limit]] system, the smallest distinctly [[consistent]] in the [[19-odd-limit]] and consistent to the [[21-odd-limit]]. It shares the same [[5/1|5th]] and [[7/1|7th]] [[Harmonic series|harmonics]] with [[31edo]] (217 = 7 × 31), as well as the [[11/9]] interval (supporting the [[31-comma temperaments #Birds|birds temperament]]). However, compared to 31edo, its [[patent val]] differ on the mappings for [[3/1|3]], [[11/1|11]], [[13/1|13]], [[17/1|17]] and [[19/1|19]] – in fact, this edo has a very accurate 13th harmonic, as well as the [[19/15]] interval. |
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| It tempers out the [[parakleisma]], {{monzo| 8 14 -13 }}, and the [[escapade comma]], {{monzo| 32 -7 -9 }} in the 5-limit; [[3136/3125]], [[4375/4374]], [[10976/10935]] and 823543/819200 in the 7-limit; [[441/440]], [[4000/3993]], 5632/5625, and [[16384/16335]] in the 11-limit; [[364/363]], [[676/675]], [[1001/1000]], [[1575/1573]], [[2080/2079]] and [[4096/4095]] in the 13-limit; 595/594, [[833/832]], [[936/935]], 1156/1155, [[1225/1224]], [[1701/1700]] in the 17-limit; 343/342, 476/475, 969/968, [[1216/1215]], [[1445/1444]], [[1521/1520]] and 1540/1539 in the 19-limit. It allows [[gentle chords]], [[werckismic chords]], and [[sinbadmic chords]] in the 13-odd-limit, in addition to [[island chords]] and [[nicolic chords]] in the 15-odd-limit. It provides the [[optimal patent val]] for the 11- and 13-limit [[arch]] and the 11- and 13-limit [[cotoneum]].
| | The equal temperament tempers out the [[parakleisma]], {{monzo| 8 14 -13 }}, and the [[escapade comma]], {{monzo| 32 -7 -9 }} in the 5-limit; [[3136/3125]], [[4375/4374]], [[10976/10935]] and 823543/819200 in the 7-limit; [[441/440]], [[4000/3993]], 5632/5625, and [[16384/16335]] in the 11-limit; [[364/363]], [[676/675]], [[1001/1000]], [[1575/1573]], [[2080/2079]] and [[4096/4095]] in the 13-limit; 595/594, [[833/832]], [[936/935]], 1156/1155, [[1225/1224]], [[1701/1700]] in the 17-limit; 343/342, 476/475, 969/968, [[1216/1215]], [[1445/1444]], [[1521/1520]] and 1540/1539 in the 19-limit. It allows [[gentle chords]], [[werckismic chords]], and [[sinbadmic chords]] in the 13-odd-limit, in addition to [[island chords]] and [[nicolic chords]] in the 15-odd-limit. It provides the [[optimal patent val]] for the 11- and 13-limit [[arch]] and the 11- and 13-limit [[cotoneum]]. |
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| === Prime harmonics === | | === Prime harmonics === |
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| == JI approximation == | | == JI approximation == |
| === Selected just intervals === | | === Selected just intervals === |
| The following table shows how [[23-odd-limit|23-odd-limit intervals]] are represented in 217EDO. Prime harmonics are in '''bold'''; inconsistent intervals are in ''italic''. | | The following table shows how [[23-odd-limit|23-odd-limit intervals]] are represented in 217edo. Prime harmonics are in '''bold'''; inconsistent intervals are in ''italic''. |
| | | {{15-odd-limit|217|23}} |
| {| class="wikitable center-all" | |
| |+Direct mapping (even if inconsistent)
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| ! Interval, complement
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| ! Error (abs, [[cent|¢]])
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| |-
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| | '''[[16/13]], [[13/8]]'''
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| | '''0.025'''
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| |-
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| | [[19/15]], [[30/19]]
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| | 0.028
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| |-
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| | [[10/9]], [[9/5]]
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| | 0.085
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| |-
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| | [[17/13]], [[26/17]]
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| | 0.088
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| |-
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| | '''[[17/16]], [[32/17]]'''
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| | '''0.114'''
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| |-
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| | [[24/17]], [[17/12]]
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| | 0.235
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| |-
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| | [[20/19]], [[19/10]]
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| | 0.321
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| |-
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| | [[13/12]], [[24/13]]
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| | 0.324
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| |-
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| | '''[[4/3]], [[3/2]]'''
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| | '''0.349'''
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| |-
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| | [[19/18]], [[36/19]]
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| | 0.406
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| |-
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| | [[6/5]], [[5/3]]
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| | 0.434
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| |-
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| | [[23/22]], [[44/23]]
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| | 0.463
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| |-
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| | [[15/11]], [[22/15]]
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| | 0.545
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| |-
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| | [[22/19]], [[19/11]]
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| | 0.573
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| |-
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| | [[18/17]], [[17/9]]
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| | 0.585
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| |-
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| | [[20/17]], [[17/10]]
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| | 0.669
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| |-
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| | [[18/13]], [[13/9]]
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| | 0.673
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| |-
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| | [[9/8]], [[16/9]]
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| | 0.698
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| |-
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| | [[21/16]], [[32/21]]
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| | 0.735
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| |-
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| | [[24/19]], [[19/12]]
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| | 0.755
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| |-
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| | [[26/21]], [[21/13]]
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| | 0.760
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| |-
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| | [[13/10]], [[20/13]]
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| | 0.758
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| |-
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| | '''[[5/4]], [[8/5]]'''
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| | '''0.783'''
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| |-
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| | [[21/17]], [[34/21]]
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| | 0.849
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| |-
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| | [[11/10]], [[20/11]]
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| | 0.894
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| |-
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| | [[11/9]], [[18/11]]
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| | 0.979
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| |-
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| | [[19/17]], [[34/19]]
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| | 0.991
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| |-
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| | [[30/23]], [[23/15]]
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| | 1.008
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| |-
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| | [[17/15]], [[30/17]]
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| | 1.018
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| |-
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| | [[23/19]], [[38/23]]
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| | 1.036
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| |-
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| | [[26/19]], [[19/13]]
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| | 1.079
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| |-
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| | '''[[8/7]], [[7/4]]'''
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| | '''1.084'''
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| |-
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| | '''[[19/16]], [[32/19]]'''
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| | '''1.104'''
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| |-
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| | [[15/13]], [[26/15]]
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| | 1.107
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| |-
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| | [[14/13]], [[13/7]]
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| | 1.109
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| |-
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| | [[16/15]], [[15/8]] | |
| | 1.132 | |
| |-
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| | [[17/14]], [[28/17]]
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| | 1.198
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| |-
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| | [[12/11]], [[11/6]]
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| | 1.328
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| |-
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| | [[23/20]], [[40/23]]
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| | 1.357
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| |-
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| | [[7/6]], [[12/7]]
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| | 1.433
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| |-
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| | [[23/18]], [[36/23]]
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| | 1.442
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| |-
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| | [[21/20]], [[40/21]]
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| | 1.518
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| |-
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| | [[22/17]], [[17/11]]
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| | 1.564
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| |-
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| | [[13/11]], [[22/13]]
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| | 1.652
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| |-
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| | '''[[11/8]], [[16/11]]'''
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| | '''1.677'''
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| |-
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| | [[9/7]], [[14/9]]
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| | 1.782
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| |-
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| | [[24/23]], [[23/12]]
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| | 1.791
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| |-
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| | [[21/19]], [[38/21]]
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| | 1.839
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| |-
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| | [[7/5]], [[10/7]]
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| | 1.867
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| |-
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| | [[23/17]], [[34/23]]
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| | 2.027
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| |-
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| | [[26/23]], [[23/13]]
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| | 2.115
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| |-
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| | '''[[32/23]], [[23/16]]'''
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| | '''2.140'''
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| |-
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| | [[19/14]], [[28/19]]
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| | 2.188
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| |-
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| | [[15/14]], [[28/15]]
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| | 2.216
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| |-
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| | ''[[28/23]], [[23/14]]''
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| | ''2.306''
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| |-
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| | [[22/21]], [[21/11]]
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| | 2.412
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| |-
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| | ''[[23/21]], [[42/23]]''
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| | ''2.655''
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| |-
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| | [[14/11]], [[11/7]]
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| | 2.761
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| |}
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| == Regular temperament properties == | | == Regular temperament properties == |
| {| class="wikitable center-4 center-5 center-6" | | {| class="wikitable center-4 center-5 center-6" |
| ! rowspan="2" | Subgroup | | ! rowspan="2" | [[Subgroup]] |
| ! rowspan="2" | [[Comma list]] | | ! rowspan="2" | [[Comma list|Comma List]] |
| ! rowspan="2" | [[Mapping]] | | ! rowspan="2" | [[Mapping]] |
| ! rowspan="2" | Optimal 8ve <br>stretch (¢) | | ! rowspan="2" | Optimal 8ve <br>Stretch (¢) |
| ! colspan="2" | Tuning error | | ! colspan="2" | Tuning Error |
| |- | | |- |
| ! [[TE error|Absolute]] (¢) | | ! [[TE error|Absolute]] (¢) |
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| |+Table of rank-2 temperaments by generator | | |+Table of rank-2 temperaments by generator |
| ! Periods<br>per 8ve | | ! Periods<br>per 8ve |
| ! Generator<br>(reduced) | | ! Generator<br>(Reduced) |
| ! Cents<br>(reduced) | | ! Cents<br>(Reduced) |
| ! Associated<br>ratio | | ! Associated<br>Ratio |
| ! Temperaments | | ! Temperaments |
| |- | | |- |
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| | 497.70 | | | 497.70 |
| | 4/3 | | | 4/3 |
| | [[Gary]] / [[cotoneum]] | | | [[Cotoneum]] |
| |- | | |- |
| | 1 | | | 1 |
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| * [[Cotoneum53]] | | * [[Cotoneum53]] |
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| [[Category:217edo| ]]<!-- main article -->
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| [[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->
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| [[Category:Arch]] | | [[Category:Arch]] |
| [[Category:Birds]] | | [[Category:Birds]] |
| [[Category:Cotoneum]] | | [[Category:Cotoneum]] |