Sensipent family: Difference between revisions
add canonical extension of sensipent to prime 31 which preserves accuracy and the "pent" can still refer to being primarily 5-limit (as we only add a relevant & accurate large prime). also add extension to 2.3.5.11.17.31 that really deserves documentation and explain the commonness and strange indirect accuracy of this 5-limit structure in terms of higher-limit harmony. |
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: mapping generators: ~2, ~125/81 | : mapping generators: ~2, ~125/81 | ||
[[Optimal tuning]] ([[POTE]]): | [[Optimal tuning]] ([[POTE]]): 2 = 1\1, ~162/125 = 443.058 | ||
{{Optimal ET sequence|legend=1| 8, 19, 46, 65, 539, 604c, 669c, 734c, 799c, 864c, 929c }} | {{Optimal ET sequence|legend=1| 8, 19, 46, 65, 539, 604c, 669c, 734c, 799c, 864c, 929c }} | ||
[[Badness]]: 0.035220 | [[Badness]]: 0.035220 | ||
Badness (Dirichlet): 0.826 | |||
=== 2.3.5.31 === | |||
Fascinatingly, essentially the only extension that preserves the occurrence of sensi's 5-limit structure in such large edos as [[539edo|539]] is the one to prime 31 by interpreting the generator accurately as [[40/31]]~[[31/24]] by tempering [[961/960|S31 = 961/960]], so that the large [[31-limit]] quarter-tones [[32/31]] and [[31/30]] are equated. For a less sparse subgroup present in smaller edo tunings like [[111edo]] at the cost of slight accuracy, see the extension to the 2.3.5.11.17.31 subgroup [[#Sensible]]. | |||
[[Subgroup]]: 2.3.5.31 | |||
[[Comma list]]: 78732/78125, 961/960 | |||
=== Sensible === | |||
An extension of sensipent to prime 11 of dubious canonicity (but significantly higher accuracy than [[sensi]]) interprets the generator as [[165/128]]~[[128/99]] by tempering [[8019/8000|S9/S10]] so that [[11/8]] is reached as ([[10/9]])<sup>3</sup>. This extension is very strong as supported by the [[optimal ET sequence]] going very far and as supported by another observation: that it is equivalent to tempering the [[semiporwellisma]] which as it is equal to [[961/960|S31]] * [[1024/1023|S32]]<sup>2</sup> (thus forming the S-expression-based comma list), which by the equivalence of the aforementioned [[lopsided comma]] also implies that this temperament equates ([[33/32]])<sup>2</sup> with [[16/15]] as well as that a natural extension to prime 31 exists through {S31, S32}, which we will see is very accurate, but this itself suggests that an extension to prime 17 is reasonably accurate through tempering [[1089/1088|S33]] so that a slightly sharp ~[[22/17]] is equated with the generator. | |||
[[Subgroup]]: 2.3.5.11 | |||
[[Comma list]]: [[8019/8000]], [[16384/16335]] | |||
{{Mapping|legend=1| 1 6 8 -6 | 0 -7 -9 15 }} | |||
{{Optimal ET sequence|legend=1| 19, 46, 65, 176, 241, 306 }} | |||
[[Optimal tuning]] ([[CTE]]): 2 = 1\1, ~128/99 = 443.115 | |||
Badness (Dirichlet): 0.728 | |||
=== 2.3.5.11.17 === | |||
The aforementioned extension to prime 17 through tempering [[1089/1088|S33]] is equivalent to the one by tempering [[256/255|S16]] = [[256/255]] = ([[22/17]])/([[165/128]]). | |||
[[Subgroup]]: 2.3.5.11.17 | |||
[[Comma list]]: [[8019/8000]], [[16384/16335]], [[256/255]] | |||
{{Mapping|legend=1| 1 6 8 -6 -6 | 0 -7 -9 15 16 }} | |||
{{Optimal ET sequence|legend=1| 19, 46, 65, 111, 176g }} | |||
[[Optimal tuning]] ([[CTE]]): 2 = 1\1, ~22/17 = 443.188 | |||
Badness (Dirichlet): 0.639 | |||
=== 2.3.5.11.17.31 === | |||
Sensible uses the accurate mapping of prime 31 in sensipent, so that the sensible generator serves many roles in subgroup harmony without the need for interpreting it as high-damage ~[[9/7]] or ~[[13/10]] intervals. Its S-expression-based comma list is {([[256/255|S16]],) [[961/960|S31]], [[1024/1023|S32]], [[1089/1088|S33]]} implying also tempering [[496/495|496/495 = S31 * S32]] and [[528/527|528/527 = S32 * S33]] as well as [[16337/16335|16337/16335 = S31/S33]] = ([[17/15|34/30]])/([[33/31]])<sup>2</sup> = ([[17/15]])/([[33/31]])<sup>2</sup>. | |||
[[Subgroup]]: 2.3.5.11.17.31 | |||
[[Comma list]]: [[8019/8000]], [[16384/16335]], [[256/255]], [[]] | |||
{{Mapping|legend=1| 1 6 8 -6 -6 | 0 -7 -9 15 16 }} | |||
{{Optimal ET sequence|legend=1| 19, 46, 65, 111, 176g, 287cg }} | |||
[[Optimal tuning]] ([[CTE]]): 2 = 1\1, ~31/24 = 443.185 | |||
Badness (Dirichlet): 0.519 | |||
== Sensi == | == Sensi == |