4th-octave temperaments: Difference between revisions
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{{ | {{Infobox fractional-octave|4}}[[4edo]] is much less used as a scale, rather as a chord. In many [[5L 2s|diatonic-based]] [[interval region]] schemes, one step of 4edo is known as a minor third, and the stacking of them is the diminished seventh chord. | ||
Usage of the [[6/5]] minor third as one step of 4edo by tempering out [[648/625]], and therefore using 4edo as a diminished seventh chord produced by stacking three minor thirds is one of the features of standard Western music theory, and is supported by [[12edo]]. See [[Diminished family]] for a collection of such temperaments. | |||
Usage of the [[6/5]] minor third as one step of 4edo by tempering out [[648/625]], and therefore using 4edo as a diminished seventh chord produced by stacking three minor thirds is one of the features of standard Western music theory, and is supported by [[12edo]]. See [[ | |||
[[19/16]], the 19th harmonic octave-reduced, is much closer to quarter-octave than 6/5, and while it is not a microtemperament, a lot of equal divisions support it. | [[19/16]], the 19th harmonic octave-reduced, is much closer to quarter-octave than 6/5, and while it is not a microtemperament, a lot of equal divisions support it. | ||
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{{Mapping|legend=1| 4 6 9 0 | 0 0 0 1 }} | {{Mapping|legend=1| 4 6 9 0 | 0 0 0 1 }} | ||
[[Optimal tuning]] ([[POTE]]): ~6/5 = 1\4, ~8/7 = 324.482 | [[Optimal tuning]] ([[POTE]]): ~6/5 = 1\4, ~8/7 = 324.482 | ||
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=== 2.3.35.11.19 subgroup === | === 2.3.35.11.19 subgroup === | ||
668edo does not map 36/35 consistently, with direct | 668edo does not map 36/35 consistently, with its own [[direct approximation]] being 27 steps while the direct approximations of its constituent odd harmonics do not sum to that same amount: 3/2, 8/5, and 8/7 are 391, 453, and 129 steps, respectively, and 391 + 391 + 453 + 129 - 668 - 668 = 28, ≠ 27. | ||
Subgroup: 2.3.35.11.19 | Subgroup: 2.3.35.11.19 | ||
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[[Support]]ing [[ET]]s: {{EDOs|24, 668}}, ... | [[Support]]ing [[ET]]s: {{EDOs|24, 668}}, ... | ||
{{Navbox fractional-octave}} | |||
{{Todo| review }} | {{Todo| review }} |