Tetracot: Difference between revisions

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'''Tetracot''', in this article, is the rank-2 [[regular temperament]] for the 2.3.5.11.13 [[subgroup]] defined by [[tempering out]] [[100/99]], [[144/143]], and [[243/242]].
'''Tetracot''', in this article, is the rank-2 [[regular temperament]] for the 2.3.5.11.13 [[subgroup]] defined by [[tempering out]] [[100/99]], [[144/143]], and [[243/242]].


It can be seen as implying a rank-2 tuning which is [[generator|generated]] by a sub-major second of about 176 [[cent]]s which represents both [[10/9]] and [[11/10]]. It is so named because the generator is a quarter of fifth: four generators make a fifth which approximates [[3/2]], which cannot occur in [[12edo]]. Equal temperaments that support tetracot include {{EDOs| 27, 34, and 41 }}.
It can be seen as implying a rank-2 tuning which is [[generator|generated]] by a sub-major second of about 176{{c}} which represents both [[10/9]] and [[11/10]]. It is so named because the generator is a quarter of fifth: four generators make a fifth which approximates [[3/2]], which cannot occur in [[12edo]]. Equal temperaments that support tetracot include {{EDOs| 27, 34, and 41 }}.


Tetracot has many [[extension]]s for the 7-, 11- and 13-limit. See [[Tetracot extensions]].  
Tetracot has many [[extension]]s for the 7-, 11- and 13-limit. See [[Tetracot extensions]].  


See [[Tetracot family]] or [[No-sevens subgroup temperaments #Tetracot]] for more technical data.
See [[Tetracot family]] or [[No-sevens subgroup temperaments#Tetracot]] for more technical data.


== Interval chain ==
== Interval chain ==
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{| class="wikitable right-1 right-2"
{| class="wikitable right-1 right-2"
|-
|-
! #
! #
! Cents<nowiki>*</nowiki>
! Cents*
! Approximate Ratios
! Approximate Ratios
|-
|-
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| 15/13
| 15/13
|}
|}
: <nowiki>*</nowiki> in 2.3.5.11.13 subgroup CTE tuning
<nowiki />* In 2.3.5.11.13 subgroup CTE tuning


== Scales ==
== Scales ==
* [[Tetracot7]] [[6L 1s]] scale
* [[Tetracot7]] &ndash; [[6L 1s]] scale
* [[Tetracot13]] improper [[7L 6s]]
* [[Tetracot13]] &ndash; improper [[7L 6s]]
* [[Tetracot20]] improper [[7L 13s]]
* [[Tetracot20]] &ndash; improper [[7L 13s]]


== Tunings ==
== Tunings ==
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{| class="wikitable center-all left-4"
{| class="wikitable center-all left-4"
|-
|-
! Edo<br>Generator
! Edo<br />Generator
! [[Eigenmonzo|Eigenmonzo<br>(Unchanged-interval)]]<nowiki>*</nowiki>
! [[Eigenmonzo|Eigenmonzo<br />(Unchanged-interval)]]*
! Generator (¢)
! Generator (¢)
! Comments
! Comments
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|  
|  
| 171.429
| 171.429
| Lower bound of 2.3.5.11 subgroup 11-odd-limit, <br>2.3.5.11.13 subgroup 13- and 15-odd-limit diamond monotone
| Lower bound of 2.3.5.11 subgroup 11-odd-limit, <br />2.3.5.11.13 subgroup 13- and 15-odd-limit diamond monotone
|-
|-
|  
|  
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|  
|  
|}
|}
<nowiki>*</nowiki> besides the octave
<nowiki />* Besides the octave


== Music ==
== Music ==
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[[Category:Temperaments]]
[[Category:Temperaments]]
[[Category:Tetracot| ]] <!-- main article -->
[[Category:Tetracot| ]] <!-- Main article -->
[[Category:Tetracot family]]
[[Category:Tetracot family]]

Revision as of 21:19, 13 November 2024

Tetracot, in this article, is the rank-2 regular temperament for the 2.3.5.11.13 subgroup defined by tempering out 100/99, 144/143, and 243/242.

It can be seen as implying a rank-2 tuning which is generated by a sub-major second of about 176 ¢ which represents both 10/9 and 11/10. It is so named because the generator is a quarter of fifth: four generators make a fifth which approximates 3/2, which cannot occur in 12edo. Equal temperaments that support tetracot include 27, 34, and 41.

Tetracot has many extensions for the 7-, 11- and 13-limit. See Tetracot extensions.

See Tetracot family or No-sevens subgroup temperaments#Tetracot for more technical data.

Interval chain

Tetracot is considered as a cluster temperament with seven clusters of notes in an octave. The chroma interval between adjacent notes in each cluster represents 40/39 ~ 45/44 ~ 55/54 ~ 65/64 ~ 66/65 ~ 81/80 ~ 121/120 all tempered together. In the following table, odd harmonics and subharmonics 1–15 are in bold.

# Cents* Approximate Ratios
0 0.00 1/1
1 175.8 11/10, 10/9
2 350.6 11/9, 16/13
3 527.4 15/11
4 703.3 3/2
5 879.1 5/3
6 1054.9 11/6, 24/13
7 30.7 55/54, 45/44, 40/39
8 206.5 9/8
9 382.3 5/4
10 558.2 11/8, 18/13
11 734.0 20/13
12 909.8 22/13
13 1085.6 15/8
14 61.4 33/32, 27/26, 25/24
15 237.2 15/13

* In 2.3.5.11.13 subgroup CTE tuning

Scales

Tunings

Tuning spectrum

Edo
Generator
Eigenmonzo
(Unchanged-interval)
*
Generator (¢) Comments
11/10 165.004
1\7 171.429 Lower bound of 2.3.5.11 subgroup 11-odd-limit,
2.3.5.11.13 subgroup 13- and 15-odd-limit diamond monotone
11/9 173.704
11/6 174.894
7\48 175.000
11/8 175.132 2.3.5.11 subgroup 11-odd-limit minimax
3/2 175.489
6\41 175.610
13/11 175.899 2.3.5.11.13 subgroup 13- and 15-odd-limit minimax
15/8 176.021
5/4 176.257 5-odd-limit and 5-limit 9-odd-limit minimax
13/9 176.338
5\34 176.471
15/13 176.516
5/3 176.872
13/10 176.890
13/12 176.905
4\27 177.778 Upper bound of 2.3.5.11.13 subgroup 13- and 15-odd-limit diamond monotone
15/11 178.984
13/8 179.736
3\20 180.000 Upper bound of 2.3.5.11 subgroup 11-odd-limit diamond monotone
9/5 182.404

* Besides the octave

Music

Flora Canou
Zhea Erose
Xotla
  • "Electrostat" from Lesser Groove (2020) – Spotify | Bandcamp | YouTube – ambient electro, tetracot[13] in 34edo tuning