Hemimean clan: Difference between revisions
m →Mediantone: correction |
→Didacus: make didacus extension to prime 11 canonical given extreme efficiency of tempering (11/4)/(7/5)^3 in the 2.7/5.11 subgroup, note this in description, review of descriptions generally. also link commas as they are interesting & useful for understanding this tempered structure |
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== Didacus == | == Didacus == | ||
In the no-3's [[11-limit]], there is a natural extension with prime 11 by equating [[25/16]] (which is already tuned sharp anyways) with [[11/7]] by tempering out [[176/175]], which is the same route that [[undecimal meantone]] uses, as this is essentially a no-3's restriction of undecimal meantone in the 11-limit, except that undecimal meantone finds ~[[28/25]] at 2 generators (as a flat ~[[9/8]]) while here it is the generator. This is equivalent to finding [[11/4]] as ([[7/5]])<sup>3</sup> In the no-3's 19-limit extension "mediantone", this whole tone generator serves as the two simplest [[mediant]]s of [[9/8]] and [[10/9]], namely [[19/17]] and [[28/25]], while in didacus and its extension to the no-3's 13-limit called roulette only the latter interpretation is relevant. | |||
[[Subgroup]]: 2.5.7 | [[Subgroup]]: 2.5.7 | ||
[[Comma list]]: 3136/3125 | [[Comma list]]: [[3136/3125]] | ||
{{Mapping|legend=2| 1 0 -3 | 0 2 5 }} | {{Mapping|legend=2| 1 0 -3 | 0 2 5 }} | ||
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[[Badness]] (Dirichlet): 0.091 | [[Badness]] (Dirichlet): 0.091 | ||
=== | === 2.5.7.11 subgroup === | ||
Subgroup: 2.5.7.11 | Subgroup: 2.5.7.11 | ||
Comma list: 176/175, 1375/1372 | Comma list: [[176/175]], [[1375/1372]] | ||
Sval mapping: {{mapping| 1 0 -3 -7 | 0 2 5 9 }} | Sval mapping: {{mapping| 1 0 -3 -7 | 0 2 5 9 }} | ||
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Badness (Dirichlet): 0.195 | Badness (Dirichlet): 0.195 | ||
==== | ==== Roulette ==== | ||
Roulette is essentially [[hemiwur]] without a mapping for prime 3. The mapping of prime 13 is somewhat strange, because it is the only mapping that requires a negative amount of generators, and not by an insignificant amount, but it can be rationalized in a variety of ways, such as that because [[~]][[8/7]] is already tuned considerably flat, it makes sense to equate two of it with [[13/10]], as this is also how we find [[22/17]] in the no-3's 17-limit extension called mediantone. The mapping of 13 increases the [[badness]] of the temperament as a result. | |||
Subgroup: 2.5.7.11.13 | Subgroup: 2.5.7.11.13 | ||
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==== Mediantone ==== | ==== Mediantone ==== | ||
Mediantone is named after its whole tone generator serving as the [[mediant]] of [[9/8]] and [[10/9]], namely [[19/17]], in addition to [[28/25]], as well as by the observation that this temperament seems to have been repeatedly rediscovered in parts in a variety of contexts, so that it seems to exist as a "median" of all of these temperaments' logics. It is also an intentional play on "[[meantone]]", as the context one is most likely to first discover this logic is when the tone also represents [[10/9]][[~]][[9/8]]. | Mediantone is named after its whole tone generator serving as the [[mediant]] of [[9/8]] and [[10/9]], namely [[19/17]], in addition to [[28/25]], as well as by the observation that this temperament seems to have been repeatedly rediscovered in parts in a variety of contexts, so that it seems to exist as a "median" of all of these temperaments' logics. It is also an intentional play on "[[meantone]]", as the context one is most likely to first discover this logic is when the tone also represents [[~]][[10/9]][[~]][[9/8]]. | ||
In the full no-3's [[19-limit]], this temperament is a structure common to quite a few temperaments. It is a rank-2 version of [[orion]] with a mapping for primes 11 and 13. It is a no-3's version of 19-limit [[grosstone]] which can be seen as an extension of [[undecimal meantone]] according to the "mediant-tone" logic of this temperament, and which as aforementioned effectively doubles the complexity of the temperament as a result of finding the generator of [[~]][[19/17]][[~]][[28/25]] as ([[~]][[3/2]])<sup>2</sup>/[[2/1|2]]. It does not work so well as an extension for [[hemiwur]] to the full 19-limit, but if you want to try anyway, a notable patent-val tuning is [[37edo]], which finds prime 3 through the [[würschmidt]] mapping so that [[6/1]] is found at 16 generators. | In the full no-3's [[19-limit]], this temperament is a structure common to quite a few temperaments. It is a rank-2 version of [[orion]] with a mapping for primes 11 and 13. It is a no-3's version of 19-limit [[grosstone]] which can be seen as an extension of [[undecimal meantone]] according to the "mediant-tone" logic of this temperament, and which as aforementioned effectively doubles the complexity of the temperament as a result of finding the generator of [[~]][[19/17]][[~]][[28/25]] as ([[~]][[3/2]])<sup>2</sup>/[[2/1|2]]. It does not work so well as an extension for [[hemiwur]] to the full 19-limit, but if you want to try anyway (at the cost of primes 17 and 19), a notable patent-val tuning is [[37edo]], which finds prime 3 through the [[würschmidt]] mapping so that [[6/1]] is found at 16 generators. | ||
Subgroup: 2.5.7.11.13.17 | Subgroup: 2.5.7.11.13.17 | ||
Comma list: 176/175, 640/637, 221/220, 1375/1372 | Comma list: [[176/175]], [[640/637]], [[221/220]], [[1375/1372]] | ||
Sval mapping: {{mapping| 1 0 -3 -7 13 -18 | 0 2 5 9 -8 19 }} | Sval mapping: {{mapping| 1 0 -3 -7 13 -18 | 0 2 5 9 -8 19 }} | ||
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Badness (Dirichlet): 0.612 | Badness (Dirichlet): 0.612 | ||
==== 2.5.7.11.13.17.19 subgroup ==== | ===== 2.5.7.11.13.17.19 subgroup ===== | ||
Subgroup: 2.5.7.11.13.17.19 | Subgroup: 2.5.7.11.13.17.19 | ||
Comma list: 176/175, 640/637, 221/220, 476/475, 1375/1372 | Comma list: [[176/175]], [[640/637]], [[221/220]], [[476/475]], [[1375/1372]] | ||
Sval mapping: {{mapping| 1 0 -3 -7 13 -18 -19 | 0 2 5 9 -8 19 20 }} | Sval mapping: {{mapping| 1 0 -3 -7 13 -18 -19 | 0 2 5 9 -8 19 20 }} | ||