Pentadacus: Difference between revisions
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'''Pentadacus''' is a [[nonoctave]] [[regular temperament]] in the 5.7.11 [[subgroup]] which tempers out the comma [[831875/823543]]. It is even more exotic than [[Bohlen-Pierce]], lacking both [[2/1]] and [[3/1]], and typically it would be used with an [[equave]] of [[5/1]], also known as the pentave. It is generated by a [[meantone]]-esque small whole tone interval that represents [[55/49]]. Stacking 3 of these tones gives [[7/5]] and 7 of them give [[11/5]] | '''Pentadacus''' is a [[nonoctave]] [[regular temperament]] in the 5.7.11 [[subgroup]] which tempers out the comma [[831875/823543]]. It is even more exotic than [[Bohlen-Pierce]], lacking both [[2/1]] and [[3/1]], and typically it would be used with an [[equave]] of [[5/1]], also known as the pentave.. It is generated by a [[meantone]]-esque small whole tone interval that represents [[55/49]]. Stacking 3 of these tones gives [[7/5]] and 7 of them give [[11/5]]. | ||
It is suitable for a harmonic system based exclusively on [https://oeis.org/wiki/5-rough_numbers 5-rough numbers] (numbers not divisible by 2 or 3), similar to how [[Bohlen-Pierce]]/[[BPS]] is suitable for a harmonic system based on odd numbers. 5:7:11(:25) could be used as the fundamental consonant chord in such a system, in the place of 3:5:7(:9) in BPS or of 4:5:6(:8) in meantone. | |||
Pentadacus is connected to the octave-repeating [[didacus]] temperament as both have a small whole tone generator for which 3 stack to 7/5, and [[didacus|undecimal didacus]] can actually be viewed not only as an extension of didacus to include the 11th harmonic, but also | Properly-tuned pentadacus generates the [[5/1]]-equivalent [[MOS scales]] [[1L 1s (5/1-equivalent)|1L 1s<5/1>]], [[1L 2s (5/1-equivalent)|1L 2s<5/1>]], etc. until ending the monolarge mos chain at [[1L 13s (5/1-equivalent)|1L 13s<5/1>]], followed by [[14L 1s (5/1-equivalent)|14L 1s<5/1>]], [[14L 15s (5/1-equivalent)|14L 15s<5/1>]]. Pentadacus has both low [[complexity]] (especially by the standards of the 5/1-equivalent world, where scales have lots of notes) and low [[error]] if tuned correctly, providing an [[efficiency|efficient]] traversal of the 5.7.11 subgroup. It was first discovered and named by [[User:CompactStar|CompactStar]] in 2026. | ||
Pentadacus can be thought of as a compressed [[14ed5]] until you hit [[5/1]], as is best exemplified by the [[1L 13s (5/1-equivalent)|1L 13s<5/1>]] Pentadacus[14] mos. Because of this, many good smaller pentadacus tunings are of the form (14''n'' + 1)ed5 such as [[29ed5]], [[43ed5]], and [[57ed5]]. In this respect, it is similar to a [[cluster temperament]], but does not seem to exactly meet the definition of a cluster temperament. 14ed5 is also close to [[6edo]], the familiar whole-tone scale with octaves, so pentadacus is very alien (being a step above even tritave-equivalent temperaments) but can lapse into sounding like the familiar whole-tone scale at times. 6 generators in pentadacus can sound a bit like a [[stretched and compressed tuning|compressed octave]] but it is usually inaccurate unless you are using a very sharp tuning like 14ed5. It should also be noted that -2 generators pentave-reduced can sound very close to [[4/1]]. | |||
Pentadacus is connected to the octave-repeating [[didacus]] temperament as both have a small whole tone generator for which 3 stack to 7/5, and [[didacus|undecimal didacus]] can actually be viewed not only as an [[extension]] of didacus to include the 11th harmonic, but also a [[weak extension]] of pentadacus to include octaves, with 2/1 being mapped to half a pentave minus one generator. Pentadacus's connection to [[14ed5]] (which is effectively 6edo with a just 5/1) is a lot like Didacus's connection to [[6edo]]. | |||
For technical data, see [[No-2s subgroup temperaments#Pentadacus]]. | |||
== Etymology == | |||
It is named as a play on [[didacus]], with the "di-" part being rebracketed as the Greek prefix for 2 and changed to "penta-" (5). | |||
== Extensions == | |||
In terms of strong extensions to the 5.7.11.13 subgroup, there are the c57 & c71 extension which maps [[13/5]] to -20 generators (but this requires the usage of the 14L 15s MOS to access 13/5), and the c15 & c29 extension which maps [[13/5]] to -6 generators (but it has high [[error]] of about 20 cents on 11/5 and 13/5). These are roughly equal in Dirichlet [[badness]]. | |||
The best extension to the 5.7.11.13 subgroup is actually the weak extension [[User:2^67-1]] has named ''Pentapassion'', that tempers out the Cuthbert comma [[847/845]]. This halves the generator into a semitone of roughly 97 cents, and 17 of these new generators reach 13/5 (so essentially 8.5 of the original generator). It is so named because the generator is close to the generator of [[Passion]] temperament (and as in septimal passion, 7/5 is mapped to 6 generators up). Interestingly, the first few steps of Pentapassion can sound like [[12edo]] (like how Pentadacus can sound like 6edo), although it quickly becomes out-of-tune after stacking a few generators. Pentapassion can be used with a 28L 1s<5/1> MOS. | |||
== Interval chain == | == Interval chain == | ||
{| class="wikitable center-1 right-2" | {| class="wikitable center-1 right-2" | ||
! # !! Cents* !! Approximate ratios | ! # !! Cents* !! Approximate ratios | ||
|- | |||
| -14||57.7||[[125/121]] | |||
|- | |||
| -13||252.6||[[625/539]] | |||
|- | |||
| -12||447.5||[[1715/1331]],[[3125/2401]] | |||
|- | |||
| -11||642.4||[[175/121]] | |||
|- | |||
| -10||837.3||[[125/77]] | |||
|- | |||
| -9||1032.2||[[625/343]] | |||
|- | |||
| -8||1227.1||[[245/121]] | |||
|- | |||
| -7||1422.0||[[25/11]] | |||
|- | |||
| -6||1616.9||[[125/49]] | |||
|- | |||
| -5|| 1811.8 ||[[343/121]], [[6875/2401]] | |||
|- | |||
| -4|| 2006.7 ||[[35/11]] | |||
|- | |||
| -3|| 2201.6||'''[[25/7]]''' | |||
|- | |||
| -2|| 2396.5||[[1375/343]] | |||
|- | |||
| -1|| 2591.4||[[49/11]] | |||
|- | |- | ||
| 0 || 0.0 || '''1/1''' | | 0 || 0.0 || '''1/1''' | ||
| Line 32: | Line 73: | ||
|4||779.6||[[11/7]] | |4||779.6||[[11/7]] | ||
|- | |- | ||
|5||974.5||[[605/343]] | |5||974.5||[[605/343]], [[2401/1375]] | ||
|- | |- | ||
|6||1169.4||[[49/25]] | |6||1169.4||[[49/25]] | ||
| Line 46: | Line 87: | ||
|11||2143.9||[[121/35]] | |11||2143.9||[[121/35]] | ||
|- | |- | ||
|12||2338.8||[[1331/343]],[[2401/625]] | |12||2338.8||[[1331/343]], [[2401/625]] | ||
|- | |- | ||
|13||2533.7||[[539/125]] | |13||2533.7||[[539/125]] | ||
| Line 56: | Line 97: | ||
|16||332.1||[[3773/3125]] | |16||332.1||[[3773/3125]] | ||
|} | |} | ||
*CWE tuning (5.7.11) | <nowiki>*</nowiki>CWE tuning (5.7.11) | ||
== Tunings == | == Tunings == | ||
=== Tuning spectrum === | === Tuning spectrum === | ||
{| class="wikitable center-all left-4" | {| class="wikitable center-all left-4" | ||
|- | |- | ||
| Line 67: | Line 107: | ||
! Generator (¢) | ! Generator (¢) | ||
! Comments | ! Comments | ||
|- | |||
| | |||
| | |||
| '''0.000''' | |||
| '''Lower bound of 5.7.11 tonality diamond monotone''' | |||
|- | |- | ||
| 1\[[15ed5]] | | 1\[[15ed5]] | ||
| | | | ||
| 185.754 | | 185.754 | ||
| | | Technically supported but below any reasonable tuning<br>11/5 has 65 cents of damage | ||
|- | |- | ||
| 2\[[29ed5]] | | 2\[[29ed5]] | ||
| | | | ||
| 192. | | 192.160 | ||
| | | | ||
|- | |||
| 7\[[101ed5]] | |||
| | |||
| 193.111 | |||
| | |||
|- | |||
| 5\[[72ed5]] | |||
| | |||
| 193.494 | |||
| | |||
|- | |- | ||
| | | | ||
| [[7/5]] | | [[7/5]] | ||
| 194.171 | | 194.171 | ||
| | |||
|- | |||
| 3\[[43ed5]] | |||
| | |||
| 194.394 | |||
| Probably the best smaller ed5 tuning | |||
|- | |||
| | |||
| [[77/25]] | |||
| 194.752 | |||
| | | | ||
|- | |- | ||
| Line 86: | Line 151: | ||
| [[11/5]] | | [[11/5]] | ||
| 195.001 | | 195.001 | ||
| | |||
|- | |||
| 7\[[100ed5]] | |||
| | |||
| 195.042 | |||
| | |||
|- | |||
| 4\[[57ed5]] | |||
| | |||
| 195.531 | |||
| | | | ||
|- | |- | ||
| Line 93: | Line 168: | ||
| | | | ||
|- | |- | ||
| | | 5\[[71ed5]] | ||
| | |||
| 196.219 | |||
| | | | ||
| | |- | ||
| 6\[[85ed5]] | |||
| | |||
| 196.268 | |||
| | |||
|- | |||
| 7\[[99ed5]] | |||
| | |||
| 197.012 | |||
| | |||
|- | |||
| '''1\[[14ed5]]''' | |||
| | | | ||
| '''199.022''' | |||
| '''Upper bound of 5.7.11 tonality diamond monotone''' | |||
|- | |- | ||
| | | | ||
| Line 107: | Line 197: | ||
[[Category:Rank-2 temperaments]] | [[Category:Rank-2 temperaments]] | ||
[[Category:Subgroup temperaments]] | [[Category:Subgroup temperaments]] | ||
[[Category:Non-octave temperaments]] | |||