28edt: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
'''28edt''' divides the [[3/1|third harmonic]] into 28 [[equal]] parts of 67.9 [[cent]]s each. It is the simplest [[edt]] which intelligibly doubles the Anti-BP harmonic chain{{clarify}} | '''28edt''' divides the [[3/1|third harmonic]] into 28 [[equal]] parts of 67.9 [[cent]]s each. It is the simplest [[edt]] which intelligibly doubles the Anti-BP harmonic chain{{clarify}}. | ||
=== | == Theory == | ||
{{Harmonics in equal|28|3}} | |||
From a no-twos perspective, 28edt has a nearly-pure 5th harmonic (which tritave-reduces to [[5/3]]), with 41/28 being a continued fraction [[convergent]] to log<sub>3</sub>(5). It poorly approximates harmonic 7, but has an acceptable approximation of harmonic 11, so it makes sense to consider it as a [[3.5.11 subgroup]] system. In the 3.5.11 subgroup, it tempers out the commas [[6655/6561]] and [[4-cent comma|1953125/1948617]]. The former means it supports [[deneb]] temperament, which equates 3 flat [[11/9]]s to [[5/3]], and the latter means it supports [[delta centauri]] temperament, which equates 9 near-just [[5/3]]s tritave-reduced to [[11/9]] (although delta centauri is a [[microtemperament]] and larger EDTs like [[71edt]] offer much better tunings of it). [[56edt]] rectifies the approximation of the 7th harmonic. | |||
28edt has a very accurate [[8/1|8th harmonic]], and as such, one step is very close to every third step of [[53edo]], and the tritave-reduced 8th harmonic [[8/3]] and tritave-reduced 8th subharmonic [[9/8]] are equally well-approximated. It tempers out the [[schisma]] in the 8.3.5 subgroup, albeit a really strange tuning due to being a multiple of 4edt and being index-2 in BP. It can also be used for the 3.8.5.11 extension of deneb temperament equating +5 generators to 8/3. | |||
Similar to how [[14edt]] can be seen as [[9edo]] with significantly [[stretched and compressed tuning|stretched]] [[octave]]s (~23{{c}}), 28edt can be seen as [[18edo]] with the same stretched octave. Note that using the stretched octave will map 8/1 to an inconsistent approximation rather than the aforementioned accurate 8/1. Considering that [[29edt]] is a compressed 18edo, neither 28edt or 29edt are truly equivalent to 18edo (these two basically correspond to 18edo's dual fifths). | |||
== Harmonics == | |||
{{Harmonics in equal | |||
| steps = 28 | |||
| num = 3 | |||
| denom = 1 | |||
| intervals = integer | |||
}} | |||
{{Harmonics in equal | |||
| steps = 28 | |||
| num = 3 | |||
| denom = 1 | |||
| start = 12 | |||
| collapsed = 1 | |||
| intervals = integer | |||
}} | |||
== Intervals == | == Intervals == | ||
{| class="wikitable right-all left-4" | {| class="wikitable right-all left-4" | ||
|- | |- | ||
! Steps | ! rowspan="2"| Steps | ||
! [[cent]]s | ! rowspan="2"| [[cent]]s | ||
! [[hekt]]s | ! rowspan="2"| [[hekt]]s | ||
! notation | ! colspan="2"| Approximate ratios | ||
! rowspan="2"| notation{{clarify}} | |||
|- | |||
!3.5.11 | |||
!3.8.5.11 | |||
|- | |- | ||
| 1 | | 1 | ||
| 67.927 | | 67.927 | ||
| 46.429 | | 46.429 | ||
| [[125/121]] | |||
| [[25/24]] | |||
| Cq/D\\y | | Cq/D\\y | ||
|- | |- | ||
| Line 21: | Line 48: | ||
| 135.854 | | 135.854 | ||
| 92.857 | | 92.857 | ||
| [[27/25]] | |||
| [[88/81]] | |||
| Cp/D\\ | | Cp/D\\ | ||
|- | |- | ||
| Line 26: | Line 55: | ||
| 203.781 | | 203.781 | ||
| 139.286 | | 139.286 | ||
| [[135/121]] | |||
| [[9/8]] | |||
| Cpq/Dy | | Cpq/Dy | ||
|- | |- | ||
| Line 31: | Line 62: | ||
| 271.708 | | 271.708 | ||
| 185.714 | | 185.714 | ||
| [[729/625]] | |||
| [[64/55]], [[75/64]] | |||
| D | | D | ||
|- | |- | ||
| Line 36: | Line 69: | ||
| 339.635 | | 339.635 | ||
| 232.143 | | 232.143 | ||
| [[11/9]] | |||
| [[40/33]] | |||
| Dp/Ey | | Dp/Ey | ||
|- | |- | ||
| Line 41: | Line 76: | ||
| 407.562 | | 407.562 | ||
| 278.571 | | 278.571 | ||
| [[125/99]] | |||
| [[81/64]] | |||
| E | | E | ||
|- | |- | ||
| Line 46: | Line 83: | ||
| 475.489 | | 475.489 | ||
| 325.000 | | 325.000 | ||
| [[33/25]] | |||
| [[72/55]], [[320/243]] | |||
| Epq/F\\y | | Epq/F\\y | ||
|- | |- | ||
| Line 51: | Line 90: | ||
| 543.416 | | 543.416 | ||
| 371.429 | | 371.429 | ||
| [[15/11]] | |||
| [[11/8]] | |||
| Ep/F\\ | | Ep/F\\ | ||
|- | |- | ||
| Line 56: | Line 97: | ||
| 611.343 | | 611.343 | ||
| 417.857 | | 417.857 | ||
| [[891/625]] | |||
| [[64/45]] | |||
| Eq/Fy | | Eq/Fy | ||
|- | |- | ||
| Line 61: | Line 104: | ||
| 679.270 | | 679.270 | ||
| 464.286 | | 464.286 | ||
| [[81/55]], [[121/81]] | |||
| [[40/27]] | |||
| F | | F | ||
|- | |- | ||
| Line 66: | Line 111: | ||
| 747.197 | | 747.197 | ||
| 510.714 | | 510.714 | ||
| [[125/81]] | |||
| [[99/64]] | |||
| Fq/Gy | | Fq/Gy | ||
|- | |- | ||
| Line 71: | Line 118: | ||
| 815.124 | | 815.124 | ||
| 557.143 | | 557.143 | ||
| [[121/75]] | |||
| [[8/5]] | |||
| G | | G | ||
|- | |- | ||
| Line 76: | Line 125: | ||
| 883.051 | | 883.051 | ||
| 603.571 | | 603.571 | ||
| [[5/3]] | |||
| | |||
| Gq/H\\y | | Gq/H\\y | ||
|- | |- | ||
| Line 81: | Line 132: | ||
| 950.978 | | 950.978 | ||
| 650.000 | | 650.000 | ||
| [[625/363]], [[1089/625]] | |||
| [[512/297]], [[891/512]] | |||
| Gp/H\\ | | Gp/H\\ | ||
|- | |- | ||
| Line 86: | Line 139: | ||
| 1018.904 | | 1018.904 | ||
| 696.429 | | 696.429 | ||
| [[9/5]] | |||
| | |||
| Gpq/Hy | | Gpq/Hy | ||
|- | |- | ||
| Line 91: | Line 146: | ||
| 1086.831 | | 1086.831 | ||
| 742.857 | | 742.857 | ||
| [[225/121]] | |||
| [[15/8]] | |||
| H | | H | ||
|- | |- | ||
| Line 96: | Line 153: | ||
| 1154.758 | | 1154.758 | ||
| 789.286 | | 789.286 | ||
| [[243/125]] | |||
| [[64/33]] | |||
| Hq/Jy | | Hq/Jy | ||
|- | |- | ||
| Line 101: | Line 160: | ||
| 1222.685 | | 1222.685 | ||
| 835.714 | | 835.714 | ||
| [[55/27]], [[243/121]] | |||
| [[81/40]] | |||
| J | | J | ||
|- | |- | ||
| Line 106: | Line 167: | ||
| 1290.612 | | 1290.612 | ||
| 882.143 | | 882.143 | ||
| [[625/297]] | |||
| [[135/64]] | |||
| Jq/A\\y | | Jq/A\\y | ||
|- | |- | ||
| Line 111: | Line 174: | ||
| 1358.539 | | 1358.539 | ||
| 928.571 | | 928.571 | ||
| [[11/5]] | |||
| [[24/11]] | |||
| Jp/A\\ | | Jp/A\\ | ||
|- | |- | ||
| Line 116: | Line 181: | ||
| 1426.466 | | 1426.466 | ||
| 975.000 | | 975.000 | ||
| [[25/11]] | |||
| [[55/24]], [[729/320]] | |||
| Jpq/Ay | | Jpq/Ay | ||
|- | |- | ||
| Line 121: | Line 188: | ||
| 1494.393 | | 1494.393 | ||
| 1021.429 | | 1021.429 | ||
| [[297/125]] | |||
| [[64/27]] | |||
| A | | A | ||
|- | |- | ||
| Line 126: | Line 195: | ||
| 1562.320 | | 1562.320 | ||
| 1067.857 | | 1067.857 | ||
| [[27/11]] | |||
| [[99/40]] | |||
| Aq/B\\y | | Aq/B\\y | ||
|- | |- | ||
| Line 131: | Line 202: | ||
| 1630.247 | | 1630.247 | ||
| 1114.286 | | 1114.286 | ||
| [[625/243]] | |||
| [[64/25]], [[165/64]] | |||
| Ap/B\\ | | Ap/B\\ | ||
|- | |- | ||
| Line 136: | Line 209: | ||
| 1698.174 | | 1698.174 | ||
| 1160.714 | | 1160.714 | ||
| [[121/45]] | |||
| [[8/3]] | |||
| Apq/By | | Apq/By | ||
|- | |- | ||
| Line 141: | Line 216: | ||
| 1766.101 | | 1766.101 | ||
| 1207.143 | | 1207.143 | ||
| [[25/9]] | |||
| [[243/88]] | |||
| B | | B | ||
|- | |- | ||
| Line 146: | Line 223: | ||
| 1834.028 | | 1834.028 | ||
| 1253.571 | | 1253.571 | ||
| [[363/125]] | |||
| [[72/25]] | |||
| Bq/Cy | | Bq/Cy | ||
|- | |- | ||
| Line 151: | Line 230: | ||
| 1901.955 | | 1901.955 | ||
| 1300.000 | | 1300.000 | ||
| [[3/1]] | |||
| | |||
| C | | C | ||
|} | |} | ||
| Line 157: | Line 238: | ||
* [http://www.seraph.it/dep/det/NonOctaveMelancholic.mp3 NonOctave Melancholic] by [[Carlo Serafini]] ([http://www.seraph.it/blog_files/06940a530481965d791c521ea45012f2-267.html blog entry]) | * [http://www.seraph.it/dep/det/NonOctaveMelancholic.mp3 NonOctave Melancholic] by [[Carlo Serafini]] ([http://www.seraph.it/blog_files/06940a530481965d791c521ea45012f2-267.html blog entry]) | ||
{{todo|expand}} | |||