Septimal ennealimma: Difference between revisions

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m redefined septiennealimmal to be more practically useful as there's no real reason to use the rank 3; it's 7/6 = 2\9 that is most useful and this allows future extension to prime 5 in non-ennealimmal ways so that the gen can be something different
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{{Infobox Interval
{{Infobox Interval
| Ratio = 40353607/40310784
| Ratio = 40353607/40310784
| Name = septimal ennealimma, septiennealimma, no-five ennealimma
| Name = septimal ennealimma, no-five ennealimma
| Color name = tritrizo comma
| Color name = tritrizo comma
| Comma = yes
| Comma = yes
}}
}}
The '''septimal ennealimma''', '''septiennealimma''' or '''no-five ennealimma''' is an unnoticeable 7-limit comma defined as 40353607/40310784 and measuring 1.838 cents. It arises as a stack between nine [[7/6]]'s and two octaves.  
The '''septimal ennealimma'''' or '''no-five ennealimma''' is an unnoticeable 7-limit comma defined as ([[7/6]])<sup>9</sup> / ([[2/1]])<sup>2</sup> and measuring 1.838 cents.


== Temperaments ==
== Temperaments ==
In the 2.3.7 subgroup, tempering it out leads to the 2.3.7 version of the [[ennealimmal temperament]], which is a member of the [[tritrizo clan]]. For edos up to circa 3000, it is tempered out if and only if the edo is divisible by 9.
In the 2.3.7 subgroup, tempering it out leads to the 2.3.7 version of the [[ennealimmal temperament]], which is a member of the [[tritrizo clan]].


In the full 7-limit, tempering it out leads to the '''septiennealimmal temperament''' (cf. septimal ennealimmal temperament). You may find a list of good equal temperaments that support this temperament below.
It can only possibly be tempered out in an EDO if that EDO is a multiple of 9. This temperament is documented below:


=== Septiennealimmal ===
=== Septiennealimmal ===
[[Subgroup]]: 2.3.5.7
The rank 2 temperament septiennealimmal is of interest to anyone who wants a different generator for the "ennealimmal-like structure" by detempering [[2401/2400|S49]] and/or because it represents the part of ennealimmal supported by non-ennealimmal EDOs of interest that do well in the 2.3.7 subgroup, such as [[36edo]], which adds [[1029/1024|S7/S8]], or [[63edo]], which in the 7-limit can be used for [[septimal magic]] and in higher limits for [[parapyth]] (among other things).


[[Mapping]]: [{{val| 9 0 0 11 }}, {{val| 0 1 0 1 }}, {{val| 0 0 1 0 }}]
[[Subgroup]]: 2.3.7


Mapping generators: ~2592/2401, ~3, ~5
[[Mapping]]: [{{val| 9 0 11 }}, {{val| 0 1 1 }}]


{{Optimal ET sequence|legend=1| 27, 45, 63, 72, 99, 171, 441, 612 }}
Generators ([[CTE]]): ~2592/2401 = (27/25)/[[2401/2400|S49]] = 1\9, ~3 = 1902.004{{cent}}


[[Badness]]: 0.502 × 10<sup>-3</sup>
[[Patent val]] non-ennealimmal EDOs with increasingly good approximations of 3: 9, 18, 36, 63, 90, 117, 135, 333, 360, 378, 747, 945, 990, 1044, 1089
 
[[Badness]]: 0.191


== See also ==
== See also ==