21edo: Difference between revisions
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== | ==Theory== | ||
Twenty-one equal divisions of the octave provides the sonic fingerprint of the augmented and 7-edo family, while also giving a some higher harmony possibilities and fun intervals like the apotome. The system can be treated as three intertwining 7-edo or "equi-heptatonic" scales, or as seven 3-edo ''augmented'' triads. The 7/4 at 968.826 cents is only off in 21-tone by 2.6 cents, which is better than any other EDO <26. | Twenty-one equal divisions of the octave provides the sonic fingerprint of the augmented and 7-edo family, while also giving a some higher harmony possibilities and fun intervals like the apotome. The system can be treated as three intertwining 7-edo or "equi-heptatonic" scales, or as seven 3-edo ''augmented'' triads. The 7/4 at 968.826 cents is only off in 21-tone by 2.6 cents, which is better than any other EDO <26. | ||
In diatonically-related terms, 21-EDO possesses four types of 2nd (subminor, minor, submajor, and supermajor), three types of 3rd (subminor, neutral, and major), a "third-fourth" (an interval that can function as either a supermajor 3rd or a narrow 4th), a wide (or acute) 4th, and a narrow tritone, as well as the octave-inversions of all of these intervals. | In diatonically-related terms, 21-EDO possesses four types of 2nd (subminor, minor, submajor, and supermajor), three types of 3rd (subminor, neutral, and major), a "third-fourth" (an interval that can function as either a supermajor 3rd or a narrow 4th), a wide (or acute) 4th, and a narrow tritone, as well as the octave-inversions of all of these intervals. | ||
| Line 17: | Line 16: | ||
The patent val for 21edo tempers out 128/125 and 2187/2000 in the 5-limit, and supplies the optimal patent val for the 5-limit [[Laconic_Family|laconic]] temperament tempering out 2187/2000, and also the optimal patent val for 7-limit, 11-limit and 13-limit laconic, spartan and gorgo temperaments. These temperaments lead to some "interesting" mappings, where 10/9 is larger than 9/8, 11/9 is larger than 16/13, and 8/7 maps to the same interval as 10/9, for instance. | The patent val for 21edo tempers out 128/125 and 2187/2000 in the 5-limit, and supplies the optimal patent val for the 5-limit [[Laconic_Family|laconic]] temperament tempering out 2187/2000, and also the optimal patent val for 7-limit, 11-limit and 13-limit laconic, spartan and gorgo temperaments. These temperaments lead to some "interesting" mappings, where 10/9 is larger than 9/8, 11/9 is larger than 16/13, and 8/7 maps to the same interval as 10/9, for instance. | ||
== Intervals == | |||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
| Line 22: | Line 22: | ||
! | Cents | ! | Cents | ||
! colspan="3" | [[Ups_and_Downs_Notation|Up/down notation]] | ! colspan="3" | [[Ups_and_Downs_Notation|Up/down notation]] | ||
! | 5L3s Octotonic Notation | ! | 5L3s Octotonic | ||
Notation | |||
! | D.-R. Interval Types | ! | D.-R. Interval Types | ||
! | Approximate Ratios *1 | ! | Approximate Ratios *1 | ||
| Line 47: | Line 48: | ||
double-down 2nd | double-down 2nd | ||
| | C | | | ^C | ||
vvD | |||
| style="text-align:center;" | C# | | style="text-align:center;" | C# | ||
| style="text-align:center;" | Subminor 2nd | | style="text-align:center;" | Subminor 2nd | ||
| Line 64: | Line 65: | ||
down 2nd | down 2nd | ||
| | | | | ^^C | ||
vD | |||
| style="text-align:center;" | Db | | style="text-align:center;" | Db | ||
| style="text-align:center;" | Minor 2nd | | style="text-align:center;" | Minor 2nd | ||
| Line 92: | Line 93: | ||
double-down 3rd | double-down 3rd | ||
| | D | | | ^D | ||
vvE | |||
| style="text-align:center;" | D# | | style="text-align:center;" | D# | ||
| style="text-align:center;" | Supermajor 2nd | | style="text-align:center;" | Supermajor 2nd | ||
| Line 109: | Line 110: | ||
down 3rd | down 3rd | ||
| | | | | ^^D | ||
vE | |||
| style="text-align:center;" | Eb | | style="text-align:center;" | Eb | ||
| style="text-align:center;" | Subminor 3rd | | style="text-align:center;" | Subminor 3rd | ||
| Line 137: | Line 138: | ||
double-down 4th | double-down 4th | ||
| | E | | | ^E | ||
vvF | |||
| style="text-align:center;" | E#/Fb | | style="text-align:center;" | E#/Fb | ||
| style="text-align:center;" | Major 3rd | | style="text-align:center;" | Major 3rd | ||
| Line 154: | Line 155: | ||
down 4th | down 4th | ||
| | | | | ^^E | ||
vF | |||
| style="text-align:center;" | F | | style="text-align:center;" | F | ||
| style="text-align:center;" | Third-Fourth | | style="text-align:center;" | Third-Fourth | ||
| Line 182: | Line 183: | ||
double-down 5th | double-down 5th | ||
| | F | | | ^F | ||
vvG | |||
| style="text-align:center;" | Gb | | style="text-align:center;" | Gb | ||
| style="text-align:center;" | Narrow Tritone | | style="text-align:center;" | Narrow Tritone | ||
| Line 199: | Line 200: | ||
down 5th | down 5th | ||
| | | | | ^^F | ||
vG | |||
| style="text-align:center;" | G | | style="text-align:center;" | G | ||
| style="text-align:center;" | Wide Tritone | | style="text-align:center;" | Wide Tritone | ||
| Line 227: | Line 228: | ||
double-down 6th | double-down 6th | ||
| | G | | | ^G | ||
vvA | |||
| style="text-align:center;" | Hb | | style="text-align:center;" | Hb | ||
| style="text-align:center;" | Fifth-Sixth | | style="text-align:center;" | Fifth-Sixth | ||
| Line 244: | Line 245: | ||
down 6th | down 6th | ||
| | | | | ^^G | ||
vA | |||
| style="text-align:center;" | H | | style="text-align:center;" | H | ||
| style="text-align:center;" | Minor 6th | | style="text-align:center;" | Minor 6th | ||
| Line 272: | Line 273: | ||
double-down 7th | double-down 7th | ||
| | A | | | ^A | ||
vvB | |||
| style="text-align:center;" | A | | style="text-align:center;" | A | ||
| style="text-align:center;" | Supermajor 6th | | style="text-align:center;" | Supermajor 6th | ||
| Line 289: | Line 290: | ||
down 7th | down 7th | ||
| | | | | ^^A | ||
vB | |||
| style="text-align:center;" | A# | | style="text-align:center;" | A# | ||
| style="text-align:center;" | Subminor 7th | | style="text-align:center;" | Subminor 7th | ||
| Line 317: | Line 318: | ||
double-down 8ve | double-down 8ve | ||
| | B | | | ^B | ||
vvC | |||
| style="text-align:center;" | B | | style="text-align:center;" | B | ||
| style="text-align:center;" | Major 7th | | style="text-align:center;" | Major 7th | ||
| Line 334: | Line 335: | ||
down 8ve | down 8ve | ||
| | | | | ^^B | ||
vC | |||
| style="text-align:center;" | B#/Cb | | style="text-align:center;" | B#/Cb | ||
| style="text-align:center;" | Supermajor 7th | | style="text-align:center;" | Supermajor 7th | ||
| Line 367: | Line 368: | ||
0-6-12 = C E G = C = C or C perfect | 0-6-12 = C E G = C = C or C perfect | ||
0-5-12 = C | 0-5-12 = C vE G = C(v3) = C down-three | ||
0-7-12 = C E | 0-7-12 = C ^E G = C(^3) = C up-three | ||
0-6-11 = C E | 0-6-11 = C E vG = C(v5) = C down-five | ||
0-7-13 = C E^ G | 0-7-13 = C ^E ^G = C(^3,^5) = C up-three up-five | ||
0-6-12-18 = C E G B = C7 = C seven | 0-6-12-18 = C E G B = C7 = C seven | ||
0-6-12-17 = C E G | 0-6-12-17 = C E G vB = C,v7 = C add down-seven | ||
0-5-12-18 = C | 0-5-12-18 = C vE G B = C7(v3) = C seven down-three | ||
0-5-12-17 = C | 0-5-12-17 = C vE G vB = Cv7 = C down-seven | ||
For a more complete list, see [[ | For a more complete list, see [[Ups and Downs Notation#Chords and Chord Progressions|Ups and Downs Notation - Chords and Chord Progressions]]. | ||
==Triadic Harmony== | ==Triadic Harmony== | ||
| Line 401: | Line 402: | ||
| style="text-align:center;" | 0-286-571 | | style="text-align:center;" | 0-286-571 | ||
| style="text-align:center;" | 23:27:32 | | style="text-align:center;" | 23:27:32 | ||
| | C | | | C vE vvG | ||
| | | | | Cv(vv5) | ||
| | C | | | C down, double-down five | ||
|- | |- | ||
| style="text-align:center;" | 0-4-11 | | style="text-align:center;" | 0-4-11 | ||
| style="text-align:center;" | 0-229-629 | | style="text-align:center;" | 0-229-629 | ||
| style="text-align:center;" | 7:8:10 | | style="text-align:center;" | 7:8:10 | ||
| | C | | | C vvE vG | ||
| | | | | Cvv(v5) | ||
| | C | | | C double-down, down five | ||
|- | |- | ||
| style="text-align:center;" | 0-6-11 | | style="text-align:center;" | 0-6-11 | ||
| style="text-align:center;" | 0-343-629 | | style="text-align:center;" | 0-343-629 | ||
| style="text-align:center;" | 9:11:13 | | style="text-align:center;" | 9:11:13 | ||
| | C E | | | C E vG | ||
| | C(v5) | | | C(v5) | ||
| | C down-five | | | C down-five | ||
| Line 422: | Line 423: | ||
| style="text-align:center;" | 0-286-743 | | style="text-align:center;" | 0-286-743 | ||
| style="text-align:center;" | 11:13:17 | | style="text-align:center;" | 11:13:17 | ||
| | C | | | C vE ^G | ||
| | | | | Cv(^5) | ||
| | C | | | C down up-five | ||
|- | |- | ||
| style="text-align:center;" | 0-8-13 | | style="text-align:center;" | 0-8-13 | ||
| style="text-align:center;" | 0-457-743 | | style="text-align:center;" | 0-457-743 | ||
| style="text-align:center;" | 13:17:20 | | style="text-align:center;" | 13:17:20 | ||
| | C | | | C vF ^G | ||
| | | | | Cv4(^5) | ||
| | C (sus) down-four up-five | | | C (sus) down-four up-five | ||
|- | |- | ||
| Line 436: | Line 437: | ||
| style="text-align:center;" | 0-286-857 | | style="text-align:center;" | 0-286-857 | ||
| style="text-align:center;" | 11:13:18 | | style="text-align:center;" | 11:13:18 | ||
| | C | | | C vE A | ||
| | A(v5) | | | A(v5) | ||
| | (inversion of 9:11:13) | | | (inversion of 9:11:13) | ||
| Line 473: | Line 474: | ||
| style="text-align:center;" | 4, 3, 2 | | style="text-align:center;" | 4, 3, 2 | ||
| style="text-align:center;" | (0)-229-400-(514) | | style="text-align:center;" | (0)-229-400-(514) | ||
| | C D^ E | | | C ^D ^E F | ||
| style="text-align:center;" | Soft diatonic | | style="text-align:center;" | Soft diatonic | ||
| | C upperfect up-2 | | | C upperfect up-2 | ||
| Line 479: | Line 480: | ||
| style="text-align:center;" | 4, 4, 1 | | style="text-align:center;" | 4, 4, 1 | ||
| style="text-align:center;" | (0)-229-457-(514) | | style="text-align:center;" | (0)-229-457-(514) | ||
| | C D^ E | | | C ^D ^^E F | ||
| style="text-align:center;" | Intense diatonic | | style="text-align:center;" | Intense diatonic | ||
| | C up-2 & 6, double-up-3 & 7 | | | C up-2 & 6, double-up-3 & 7 | ||
| Line 485: | Line 486: | ||
| style="text-align:center;" | 5, 3, 1 | | style="text-align:center;" | 5, 3, 1 | ||
| style="text-align:center;" | (0)-286-457-(514) | | style="text-align:center;" | (0)-286-457-(514) | ||
| | C D^^ E | | | C ^^D ^^E F | ||
| style="text-align:center;" | Archytas chromatic | | style="text-align:center;" | Archytas chromatic | ||
| | C double-up-2, 3, 6 and 7 | | | C double-up-2, 3, 6 and 7 | ||
| Line 491: | Line 492: | ||
| style="text-align:center;" | 5, 2, 2 | | style="text-align:center;" | 5, 2, 2 | ||
| style="text-align:center;" | (0)-286-400-(514) | | style="text-align:center;" | (0)-286-400-(514) | ||
| | C D | | | C ^D ^E F | ||
| style="text-align:center;" | Weak chromatic | | style="text-align:center;" | Weak chromatic | ||
| | C double-up 2 & 6, up-3 & 7 | | | C double-up 2 & 6, up-3 & 7 | ||
| Line 497: | Line 498: | ||
| style="text-align:center;" | 6, 2, 1 | | style="text-align:center;" | 6, 2, 1 | ||
| style="text-align:center;" | (0)-343-457-(514) | | style="text-align:center;" | (0)-343-457-(514) | ||
| | C | | | C ^<span style="font-size: 90%; vertical-align: super;">3</span>D ^^E F | ||
| style="text-align:center;" | Strong enharmonic | | style="text-align:center;" | Strong enharmonic | ||
| | C triple-up 2 & 6, double-up 3 & 7 | | | C triple-up 2 & 6, double-up 3 & 7 | ||
| Line 503: | Line 504: | ||
| style="text-align:center;" | 7, 1, 1 | | style="text-align:center;" | 7, 1, 1 | ||
| style="text-align:center;" | (0)-400-457-(514) | | style="text-align:center;" | (0)-400-457-(514) | ||
| | C | | | C ^<span style="font-size: 90%; vertical-align: super;">4</span>D ^^E F | ||
| style="text-align:center;" | Pythagorean enharmonic | | style="text-align:center;" | Pythagorean enharmonic | ||
| | C quadruple-up 2 & 6, double-up 3 & 7 | | | C quadruple-up 2 & 6, double-up 3 & 7 | ||
| Line 562: | Line 563: | ||
==Commas== | ==Commas== | ||
21 EDO tempers out the following 13-limit commas. (Note: This assumes the val < 21 33 49 59 73 78 |.) | 21 EDO tempers out the following 13-limit [[commas]]. (Note: This assumes the val < 21 33 49 59 73 78 |.) | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
! | | ! | [[Ratio]] | ||
! | Monzo | ! | [[Monzo]] | ||
! | | ! | [[Cents]] | ||
![[Color notation/Temperament Names|Color Name]] | |||
! | Name 1 | ! | Name 1 | ||
! | Name 2 | ! | Name 2 | ||
| Line 575: | Line 577: | ||
| |<nowiki> | -11 7 </nowiki>> | | |<nowiki> | -11 7 </nowiki>> | ||
| style="text-align:right;" | 113.69 | | style="text-align:right;" | 113.69 | ||
| style="text-align:center;" |Lawa | |||
| style="text-align:center;" | Apotome | | style="text-align:center;" | Apotome | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 581: | Line 584: | ||
| |<nowiki> | 7 0 -3 </nowiki>> | | |<nowiki> | 7 0 -3 </nowiki>> | ||
| style="text-align:right;" | 41.06 | | style="text-align:right;" | 41.06 | ||
| style="text-align:center;" |Trigu | |||
| style="text-align:center;" | Diesis | | style="text-align:center;" | Diesis | ||
| style="text-align:center;" | Augmented Comma | | style="text-align:center;" | Augmented Comma | ||
| Line 587: | Line 591: | ||
| |<nowiki> | -25 7 6 </nowiki>> | | |<nowiki> | -25 7 6 </nowiki>> | ||
| style="text-align:right;" | 31.57 | | style="text-align:right;" | 31.57 | ||
| style="text-align:center;" |Lala-tribiyo | |||
| style="text-align:center;" | Ampersand's Comma | | style="text-align:center;" | Ampersand's Comma | ||
| | | | | | ||
| Line 593: | Line 598: | ||
| |<nowiki> | 32 -7 -9 </nowiki>> | | |<nowiki> | 32 -7 -9 </nowiki>> | ||
| style="text-align:right;" | 9.49 | | style="text-align:right;" | 9.49 | ||
| style="text-align:center;" |Sasa-tritrigu | |||
| style="text-align:center;" | Escapade Comma | | style="text-align:center;" | Escapade Comma | ||
| | | | | | ||
| Line 599: | Line 605: | ||
| |<nowiki> | -3 1 -3 3 </nowiki>> | | |<nowiki> | -3 1 -3 3 </nowiki>> | ||
| style="text-align:right;" | 49.49 | | style="text-align:right;" | 49.49 | ||
| style="text-align:center;" |Trizogu | |||
| style="text-align:center;" | Keega | | style="text-align:center;" | Keega | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 605: | Line 612: | ||
| |<nowiki> | 2 2 -1 -1 </nowiki>> | | |<nowiki> | 2 2 -1 -1 </nowiki>> | ||
| style="text-align:right;" | 48.77 | | style="text-align:right;" | 48.77 | ||
| style="text-align:center;" |Rugu | |||
| style="text-align:center;" | Septimal Quarter Tone | | style="text-align:center;" | Septimal Quarter Tone | ||
| | | | | | ||
| Line 611: | Line 619: | ||
| |<nowiki> | -10 7 8 -7 </nowiki>> | | |<nowiki> | -10 7 8 -7 </nowiki>> | ||
| style="text-align:right;" | 22.41 | | style="text-align:right;" | 22.41 | ||
| style="text-align:center;" |Lasepru-aquadbiyo | |||
| style="text-align:center;" | Blackjackisma | | style="text-align:center;" | Blackjackisma | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 617: | Line 626: | ||
| |<nowiki> | -10 1 0 3 </nowiki>> | | |<nowiki> | -10 1 0 3 </nowiki>> | ||
| style="text-align:right;" | 8.43 | | style="text-align:right;" | 8.43 | ||
| style="text-align:center;" |Latrizo | |||
| style="text-align:center;" | Gamelisma | | style="text-align:center;" | Gamelisma | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 623: | Line 633: | ||
| |<nowiki> | -5 2 2 -1 </nowiki>> | | |<nowiki> | -5 2 2 -1 </nowiki>> | ||
| style="text-align:right;" | 7.71 | | style="text-align:right;" | 7.71 | ||
| style="text-align:center;" |Ruyoyo | |||
| style="text-align:center;" | Septimal Kleisma | | style="text-align:center;" | Septimal Kleisma | ||
| style="text-align:center;" | Marvel Comma | | style="text-align:center;" | Marvel Comma | ||
| Line 629: | Line 640: | ||
| |<nowiki> | 0 3 4 -5 </nowiki>> | | |<nowiki> | 0 3 4 -5 </nowiki>> | ||
| style="text-align:right;" | 6.99 | | style="text-align:right;" | 6.99 | ||
| style="text-align:center;" |Quinru-aquadyo | |||
| style="text-align:center;" | Mirkwai | | style="text-align:center;" | Mirkwai | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 635: | Line 647: | ||
| |<nowiki> | -5 -1 -2 4 </nowiki>> | | |<nowiki> | -5 -1 -2 4 </nowiki>> | ||
| style="text-align:right;" | 0.72 | | style="text-align:right;" | 0.72 | ||
| style="text-align:center;" |Bizozogu | |||
| style="text-align:center;" | Breedsma | | style="text-align:center;" | Breedsma | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 641: | Line 654: | ||
| |<nowiki> | 47 -7 -7 -7 </nowiki>> | | |<nowiki> | 47 -7 -7 -7 </nowiki>> | ||
| style="text-align:right;" | 0.34 | | style="text-align:right;" | 0.34 | ||
| style="text-align:center;" |Trisa-seprugu | |||
| style="text-align:center;" | Akjaysma | | style="text-align:center;" | Akjaysma | ||
| style="text-align:center;" | 5\7 Octave Comma | | style="text-align:center;" | 5\7 Octave Comma | ||
| Line 647: | Line 661: | ||
| |<nowiki> | -1 2 0 -2 1 </nowiki>> | | |<nowiki> | -1 2 0 -2 1 </nowiki>> | ||
| style="text-align:right;" | 17.58 | | style="text-align:right;" | 17.58 | ||
| style="text-align:center;" |Loruru | |||
| style="text-align:center;" | Mothwellsma | | style="text-align:center;" | Mothwellsma | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 653: | Line 668: | ||
| |<nowiki> | 4 0 -2 -1 1 </nowiki>> | | |<nowiki> | 4 0 -2 -1 1 </nowiki>> | ||
| style="text-align:right;" | 9.86 | | style="text-align:right;" | 9.86 | ||
| style="text-align:center;" |Lorugugu | |||
| style="text-align:center;" | Valinorsma | | style="text-align:center;" | Valinorsma | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 659: | Line 675: | ||
| |<nowiki> | 5 -1 3 0 -3 </nowiki>> | | |<nowiki> | 5 -1 3 0 -3 </nowiki>> | ||
| style="text-align:right;" | 3.03 | | style="text-align:right;" | 3.03 | ||
| style="text-align:center;" |Triluyo | |||
| style="text-align:center;" | Wizardharry | | style="text-align:center;" | Wizardharry | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
Revision as of 04:01, 14 December 2019
Theory
Twenty-one equal divisions of the octave provides the sonic fingerprint of the augmented and 7-edo family, while also giving a some higher harmony possibilities and fun intervals like the apotome. The system can be treated as three intertwining 7-edo or "equi-heptatonic" scales, or as seven 3-edo augmented triads. The 7/4 at 968.826 cents is only off in 21-tone by 2.6 cents, which is better than any other EDO <26.
In diatonically-related terms, 21-EDO possesses four types of 2nd (subminor, minor, submajor, and supermajor), three types of 3rd (subminor, neutral, and major), a "third-fourth" (an interval that can function as either a supermajor 3rd or a narrow 4th), a wide (or acute) 4th, and a narrow tritone, as well as the octave-inversions of all of these intervals.
In temperament terms, 21-EDO can be treated as a 13-limit temperament, but of harmonics 3, 5, 7, 11, and 13, the only harmonic 21-EDO approximates with anything approaching a near-Just flavor is the 7th harmonic. On the other hand, 21-EDO provides exceptionally accurate tunings of the 15th, 23rd, and 29th harmonics (within 3 cents or less), as well as a very reasonable approximation of the 27th harmonic (around 8 cents sharp). As such, treating 21-EDO as a 2.7.15.23.27.29 subgroup temperament allows for a more accurate rationalization of the tuning, since almost every interval in 21-EDO can be described as a ratio within the 29-odd-limit. 21-EDO also works well on the 2.9/5.11/5.13/5.17/5.35/5 subgroup, which is possibly a more sensible way to treat it.
The patent val for 21edo tempers out 128/125 and 2187/2000 in the 5-limit, and supplies the optimal patent val for the 5-limit laconic temperament tempering out 2187/2000, and also the optimal patent val for 7-limit, 11-limit and 13-limit laconic, spartan and gorgo temperaments. These temperaments lead to some "interesting" mappings, where 10/9 is larger than 9/8, 11/9 is larger than 16/13, and 8/7 maps to the same interval as 10/9, for instance.
Intervals
| Degree | Cents | Up/down notation | 5L3s Octotonic
Notation |
D.-R. Interval Types | Approximate Ratios *1 | Approximate Ratios *2 | Approximate Ratios *3 | ||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 0.00 | 1 | unison | C | C | Unison | 1/1 | 1/1 | 1/1 |
| 1 | 57.14 | ^1
vv2 |
up unison,
double-down 2nd |
^C
vvD |
C# | Subminor 2nd | 28/27, 30/29 | 35/34, 36/35 | 64/63 |
| 2 | 114.29 | ^^1
v2 |
double-up unison,
down 2nd |
^^C
vD |
Db | Minor 2nd | 16/15, 15/14, 29/27 | 18/17 | 16/15, 25/24 |
| 3 | 171.43 | 2 | 2nd | D | D | Submajor 2nd | 10/9, 32/29 | 10/9,11/10 | 9/8 |
| 4 | 228.57 | ^2
vv3 |
up 2nd,
double-down 3rd |
^D
vvE |
D# | Supermajor 2nd | 8/7 | 8/7 | 8/7, 10/9, 11/10 |
| 5 | 285.71 | ^^2
v3 |
double-up 2nd,
down 3rd |
^^D
vE |
Eb | Subminor 3rd | 27/23, 32/27 | 13/11, 20/17 | 6/5, 7/6 |
| 6 | 342.86 | 3 | 3rd | E | E | Neutral 3rd | 28/23 | 11/9 | 16/13 |
| 7 | 400 | ^3
vv4 |
up 3rd,
double-down 4th |
^E
vvF |
E#/Fb | Major 3rd | 29/23 | 44/35 | 5/4, 9/7, 11/9, 14/11 |
| 8 | 457.14 | ^^3
v4 |
double-up 3rd,
down 4th |
^^E
vF |
F | Third-Fourth | 30/23 | 13/10, 17/13, 22/17 | 13/10 |
| 9 | 514.29 | 4 | 4th | F | F# | Acute 4th | 161/120, 256/189 | 35/26 | 4/3, 18/13 |
| 10 | 571.43 | ^4
vv5 |
up 4th,
double-down 5th |
^F
vvG |
Gb | Narrow Tritone | 32/23 | 18/13 | 7/5, 11/8 |
| 11 | 628.57 | ^^4
v5 |
double-up 4th,
down 5th |
^^F
vG |
G | Wide Tritone | 23/16 | 13/9 | 10/7, 16/11 |
| 12 | 685.71 | 5 | 5th | G | G# | Grave 5th | 189/128, 240/161 | 52/35 | 3/2, 13/9 |
| 13 | 742.86 | ^5
vv6 |
up 5th,
double-down 6th |
^G
vvA |
Hb | Fifth-Sixth | 23/15 | 17/11, 20/13, 26/17 | 20/13 |
| 14 | 800 | ^^5
v6 |
double-up 5th,
down 6th |
^^G
vA |
H | Minor 6th | 46/29 | 35/22 | 8/5, 11/7, 14/9, 18/11 |
| 15 | 857.14 | 6 | 6th | A | H#/Ab | Neutral 6th | 23/14 | 18/11 | 13/8 |
| 16 | 914.29 | ^6
vv7 |
up 6th,
double-down 7th |
^A
vvB |
A | Supermajor 6th | 27/16, 46/27 | 17/10, 22/13 | 5/3, 12/7 |
| 17 | 971.43 | ^^6
v7 |
double-up 6th,
down 7th |
^^A
vB |
A# | Subminor 7th | 7/4 | 7/4 | 7/4, 9/5, 20/11 |
| 18 | 1028.57 | 7 | 7th | B | Bb | Supraminor 7th | 29/16, 9/5 | 9/5, 20/11 | 16/9 |
| 19 | 1085.71 | ^7
vv8 |
up 7th,
double-down 8ve |
^B
vvC |
B | Major 7th | 15/8 | 17/9 | 15/8, 48/25 |
| 20 | 1142.86 | ^^7
v8 |
double-up 7th,
down 8ve |
^^B
vC |
B#/Cb | Supermajor 7th | 27/14, 29/15 | 35/18, 68/35 | 63/32 |
| 21 | 1200 | 8 | 8ve | C | C | Octave | 2/1 | 2/1 | 2/1 |
∗1: based on treating 21-EDO as a 2.7.15.23.27.29 subgroup temperament
∗2: based on treating 21-EDO as a 2.9/5.11/5.13/5.17/5.35/5 subgroup temperament
∗3: based on treating 21-EDO as 13-limit laconic temperament
Chord Names
Ups and downs can be used to name 21edo chords. Because every interval is perfect, the quality can be omitted, and the words major, minor, augmented and diminished are never used.
0-6-12 = C E G = C = C or C perfect
0-5-12 = C vE G = C(v3) = C down-three
0-7-12 = C ^E G = C(^3) = C up-three
0-6-11 = C E vG = C(v5) = C down-five
0-7-13 = C ^E ^G = C(^3,^5) = C up-three up-five
0-6-12-18 = C E G B = C7 = C seven
0-6-12-17 = C E G vB = C,v7 = C add down-seven
0-5-12-18 = C vE G B = C7(v3) = C seven down-three
0-5-12-17 = C vE G vB = Cv7 = C down-seven
For a more complete list, see Ups and Downs Notation - Chords and Chord Progressions.
Triadic Harmony
One interesting feature of 21-EDO is the variety of triads it offers. Five of its intervals--228.6¢, 285.7¢, 342.9¢, 400¢, and 457.1¢ can function categorically as "3rds" for those whose ears are accustomed to diatonic interval categories, representing arto, minor, neutral, major, and tendo 3rds respectively (or double-down, down, perfect, up and double-up). One can couple these with 21-EDO's narrow fifth to form five types of triad. In addition to these, there are a few noteworthy "altered" triads that stand out as representations to parts of the overtone series:
| Steps | Cents | Ratio | Example in C | Written name | Spoken name |
|---|---|---|---|---|---|
| 0-5-10 | 0-286-571 | 23:27:32 | C vE vvG | Cv(vv5) | C down, double-down five |
| 0-4-11 | 0-229-629 | 7:8:10 | C vvE vG | Cvv(v5) | C double-down, down five |
| 0-6-11 | 0-343-629 | 9:11:13 | C E vG | C(v5) | C down-five |
| 0-5-13 | 0-286-743 | 11:13:17 | C vE ^G | Cv(^5) | C down up-five |
| 0-8-13 | 0-457-743 | 13:17:20 | C vF ^G | Cv4(^5) | C (sus) down-four up-five |
| 0-5-15 | 0-286-857 | 11:13:18 | C vE A | A(v5) | (inversion of 9:11:13) |
Moment-of-Symmetry Scales
Since 21-EDO contains sub-EDOs of 3 and 7, it contains no heptatonic MOS scales (other than 7-EDO) and a wealth of scales that repeat at a 1/3-octave period.
For 7-limit harmony (based on a chord of 0-7-12-17 approximating 4:5:6:7), using 1/3-octave period scales (i.e. those related to augmented temperament) yields the most harmonically-efficient scales. The 9-note 3L6s scale (related to Tcherepnin's scale in 12-TET) is an excellent example.
For scales with a full-octave period, only 6 degrees of 21-EDO generate unique scales: 1\21, 2\21, 4\21, 5\21, 8\21, and 10\21. Other degrees generate either 7-EDO, 3-EDO, or a repetition of one of the other scales.
Examples:
Tetrachordal Scales
While 21-EDO lacks any 7-note MOS scales, one can still construct a variety of interesting and useful 7-note scales using tetrachords instead of MOS generators. The 21-EDO fourth is 9 steps, which can be divided into three parts in the following ways:
| Step Pattern | Cents | Example | Name* | Ups/downs name |
|---|---|---|---|---|
| 3, 3, 3 | (0)-171-343-(514) | C D E F | Equable diatonic | C perfect |
| 4, 3, 2 | (0)-229-400-(514) | C ^D ^E F | Soft diatonic | C upperfect up-2 |
| 4, 4, 1 | (0)-229-457-(514) | C ^D ^^E F | Intense diatonic | C up-2 & 6, double-up-3 & 7 |
| 5, 3, 1 | (0)-286-457-(514) | C ^^D ^^E F | Archytas chromatic | C double-up-2, 3, 6 and 7 |
| 5, 2, 2 | (0)-286-400-(514) | C ^D ^E F | Weak chromatic | C double-up 2 & 6, up-3 & 7 |
| 6, 2, 1 | (0)-343-457-(514) | C ^3D ^^E F | Strong enharmonic | C triple-up 2 & 6, double-up 3 & 7 |
| 7, 1, 1 | (0)-400-457-(514) | C ^4D ^^E F | Pythagorean enharmonic | C quadruple-up 2 & 6, double-up 3 & 7 |
∗These names may not be correct in relating to the ancient Greek tetrachordal genera; please change them if you know better!
The steps of these 7 basic patterns can also be permuted/rotated to give a total of 28 tetrachords, which can then be combined in either conjunct or disjunct form to yield a staggering number of scales. Thus 21edo can do reasonably-convincing imitations of the melodic forms of various tetrachordal musical traditions, such as ancient Greek, maqam, and dastgah.
Rank two temperaments
List of 21edo rank two temperaments by badness
| Periods per octave | Generator | Temperaments |
|---|---|---|
| 1 | 1\21 | Escapade |
| 1 | 2\21 | Miracle |
| 1 | 4\21 | Slendric/Gorgo/Gidorah |
| 1 | 5\21 | Subklei |
| 1 | 8\21 | Tridec |
| 1 | 10\21 | Triton |
| 3 | 1\21 | |
| 3 | 2\21 | Augmented/August |
| 3 | 3\21 | Oodako |
| 7 | 1\21 | Whitewood |
Commas
21 EDO tempers out the following 13-limit commas. (Note: This assumes the val < 21 33 49 59 73 78 |.)
| Ratio | Monzo | Cents | Color Name | Name 1 | Name 2 |
|---|---|---|---|---|---|
| 2187/2048 | | -11 7 > | 113.69 | Lawa | Apotome | |
| 128/125 | | 7 0 -3 > | 41.06 | Trigu | Diesis | Augmented Comma |
| | -25 7 6 > | 31.57 | Lala-tribiyo | Ampersand's Comma | ||
| | 32 -7 -9 > | 9.49 | Sasa-tritrigu | Escapade Comma | ||
| 1029/1000 | | -3 1 -3 3 > | 49.49 | Trizogu | Keega | |
| 36/35 | | 2 2 -1 -1 > | 48.77 | Rugu | Septimal Quarter Tone | |
| | -10 7 8 -7 > | 22.41 | Lasepru-aquadbiyo | Blackjackisma | ||
| 1029/1024 | | -10 1 0 3 > | 8.43 | Latrizo | Gamelisma | |
| 225/224 | | -5 2 2 -1 > | 7.71 | Ruyoyo | Septimal Kleisma | Marvel Comma |
| 16875/16807 | | 0 3 4 -5 > | 6.99 | Quinru-aquadyo | Mirkwai | |
| 2401/2400 | | -5 -1 -2 4 > | 0.72 | Bizozogu | Breedsma | |
| | 47 -7 -7 -7 > | 0.34 | Trisa-seprugu | Akjaysma | 5\7 Octave Comma | |
| 99/98 | | -1 2 0 -2 1 > | 17.58 | Loruru | Mothwellsma | |
| 176/175 | | 4 0 -2 -1 1 > | 9.86 | Lorugugu | Valinorsma | |
| 4000/3993 | | 5 -1 3 0 -3 > | 3.03 | Triluyo | Wizardharry |
Books / Literature
Sword, Ron. "Icosihenaphonic Scales for Guitar". IAAA Press. 1st ed: July 2009.
Music
- Iridescent Wenge Fugue by Stephen Weigel (accepted to SEAMUS 2018 and Electroacoustic Barn Dance 2018)
- WEIGEL FAMILY CHRISTMAS (xenharmonic chocolate), an album of xenharmonic Christmas covers played by Stephen Weigel, many are in 21edo
- 21-edo Trio for Organ by Claudi Meneghin
- 21-penny jingle by Claudi Meneghin
- Short Clip of 21-edo Acoustic [dead link] by Ron Sword
- Open tuning Drone Improvisation in 21-edo [dead link] by Ron Sword
- Anomalous Readings (MP3) by Andrew Heathwaite
- Comets Over Flatland 15 by Randy Winchester
- Comets Over Flatland 18 by Randy Winchester
- L'esatonale ubriaco (the drunk hexatonal), ALIENAMENTE by Fabrizio Fulvio Fausto Fiale