Diachrome: Difference between revisions

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'''Diachrome''' (also denoted 5s in [[groundfault]]'s [[aberrismic theory]]) is a set of three 5L 2m 5s scale patterns:
'''Diachrome''' or '''chromedye''' (denoted dia5s or 5s in [[groundfault]]'s [[aberrismic theory]] systematic naming) is a set of three 5L 2m 5s [[scale pattern]]s:
* 5sL: LsLsLsmLsLsm
* 5sL: LsLsLsmLsLsm
* 5sR: LmsLsLsLmsLs
* 5sR: LmsLsLsLmsLs
* 5sC: LsLsLmsLsLsm
* 5sC: LsLsLmsLsLsm (''interchroid'' structure)
 
5sL and 5sR are [[chiral]] pairs, and 5sC is achiral. The three chiralities are also determined by the number of ms and sm substrings they have.  
5sL and 5sR are [[chiral]] pairs, and 5sC is achiral. The three chiralities are also determined by the number of ms and sm substrings they have.  


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=== Balance ===
=== Balance ===
The 5sC pattern, LsLsLmsLsLsm, is a diregular scale according to the [[Ternary scale theorems#|classification of ternary balanced scales]]. In particular, it is (as an abstract scale word) MV3 but not SV3.
The 5sC pattern, LsLsLmsLsLsm, is an even-regular scale according to the [[Ternary scale theorems#|classification of ternary balanced scales]]. In particular, it is (as an abstract scale word) MV3 but not SV3.


== Diachrome in edos ==
== Diachrome in edos ==
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Diachrome is interesting for having at least four notable JI interpretations. In all the interpretations below, L + s = 9/8, and m = 256/243.
Diachrome is interesting for having at least four notable JI interpretations. In all the interpretations below, L + s = 9/8, and m = 256/243.


=== 7-limit[5120/5103] ===
=== 7-limit [5120/5103] ===
In the 7-limit, diachrome has two JI tunings which are very similar and can be identified by tempering out [[5120/5103]], the 5.8c gap between 81/80 and 64/63. These commas are notable for being the two most common interpretations for aberrisma scale steps in [[aberrismic theory]].
In the 7-limit, diachrome has two JI tunings which are very similar and can be identified by tempering out [[5120/5103]], the 5.8{{c}} gap between 81/80 and 64/63. These commas are notable for being the two most common interpretations for aberrisma scale steps in [[aberrismic theory]].
* The 2.3.5 tuning has L = 10/9, m = 256/243, s = 81/80.
* The 2.3.5 tuning has L = 10/9, m = 256/243, s = 81/80.
* The 2.3.7 tuning has L = 567/512, m = 256/243, s = 64/63.
* The 2.3.7 tuning has L = 567/512, m = 256/243, s = 64/63.
The tempered tuning thus has the mappings
The tempered tuning thus has the mappings
* 3/2 = 3L + m + 3s,
* 3/2 = 3L + m + 3s,
* 5/4 = 2L + s,
* 5/4 = 2L + s,
* 7/4 = 4L + 2m + 3s.
* 7/4 = 4L + 2m + 3s.
The property of tempering out 5120/5103 thus lends 41edo, 46edo, 53edo, and 58edo some importance in aberrismic theory; 5120/5103 has been named the ''Aberschisma'' for this reason.
 
The property of tempering out 5120/5103 thus lends 41edo (6:3:1), 46edo (7:3:1), 53edo (8:4:1), and 58edo (9:4:1) some importance in aberrismic theory; 5120/5103 has been named the ''Aberschisma'' for this reason.


=== 2.3.7.11.13 parapyth ===
=== 2.3.7.11.13 parapyth ===
Diachrome can be given a [[parapyth]] (2.3.7.11.13[29 & 41 & 46]) tempering:
Diachrome can be given a [[parapyth]] (2.3.7.11.13[29 & 41 & 46]) tempering:
* The L step becomes 12/11
* The L step becomes 12/11;
* The m step becomes 256/243~22/21~104/99
* The m step becomes 22/21~104/99~256/243;
* The s step becomes 28/27~33/32~1053/1024
* The s step becomes 28/27~33/32~1053/1024.
 
The tempered tuning thus has the mappings
The tempered tuning thus has the mappings
* 3/2 = 3L + m + 3s,
* 3/2 = 3L + m + 3s,
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* 11/8 = 2L + m + 3s,
* 11/8 = 2L + m + 3s,
* 13/8 = 3L + 2m + 4s.  
* 13/8 = 3L + 2m + 4s.  
By not tempering out 144/143, parapyth distinguishes m + s from L by tuning the former to 13/12 and the latter to 12/11.
By not tempering out 144/143, parapyth distinguishes m + s from L by tuning the former to 13/12 and the latter to 12/11.


The 5sL version of diachrome tempered to parapyth is known by [[Margo Schulter]] under the name "Penthesilia[12]".
The 5sL version of diachrome tempered to parapyth is known by [[Margo Schulter]] under the name "Penthesilia[12]".


=== 2.3.11.19.23/5.31[17 & 24] ===
=== 2.3.11.19.23/5.31 [17 & 24] ===
There's also a diachrome tempered by an extension of [[Rastmic_clan#Neutral | neutral]] (2.3.11.19.23/5.31[17 & 24]):
There's also a diachrome tempered by an extension of [[Rastmic_clan#Neutral | neutral]] (2.3.11.19.23/5.31[17 & 24]):
* The L step is 12/11
* The L step is 12/11;
* The m step is 256/243~128/121~93/88~19/18
* The m step is 256/243~128/121~93/88~19/18;
* The s step is 33/32~32/31~95/92
* The s step is 33/32~32/31~95/92.
 
The tempered tuning thus has the mappings
The tempered tuning thus has the mappings
* 3/2 = 3L + m + 3s,
* 3/2 = 3L + m + 3s,
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* 23/20 = L + m,
* 23/20 = L + m,
* 31/16 = 5L + 2m + 4s.
* 31/16 = 5L + 2m + 4s.
Note that L = m + s in this tuning, and it makes the scales nonstrictly [[Rothenberg propriety | proper]].   
Note that L = m + s in this tuning, and it makes the scales nonstrictly [[Rothenberg propriety | proper]].   


=== 2.3.7.13.19.23[17 & 19 & 41] ===
=== 2.3.7.13.19.23 [17 & 19 & 41] ===
A diachrome is also available in the 2.3.7.13.19.23[17 & 19 & 41] tempering:
A diachrome is also available in the 2.3.7.13.19.23[17 & 19 & 41] tempering:
* The L step is 13/12
* The L step is 13/12;
* The m step is 256/243~96/91~19/18
* The m step is 256/243~96/91~19/18;
* The s step is 28/27~27/26
* The s step is 28/27~27/26.
 
The tempered tuning has the mappings
The tempered tuning has the mappings
* 3/2 = 3L + m + 3s,
* 3/2 = 3L + m + 3s,
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* 19/16 = L + m + s,
* 19/16 = L + m + s,
* 23/14 = 3L + 2m + 4s.  
* 23/14 = 3L + 2m + 4s.  
Unlike the above parapyth tempering, this one sharpens s~28/27 slightly towards 27/26 instead of flattening it towards 33/32, sharpens 32/27 slightly towards 19/16 instead of flattening it to 13/11.
Unlike the above parapyth tempering, this one sharpens s~28/27 slightly towards 27/26 instead of flattening it towards 33/32, sharpens 32/27 slightly towards 19/16 instead of flattening it to 13/11.


It tunes m + s to 23/21, therefore larger than L~13/12, and makes the scales strictly proper.
It tunes m + s to 23/21, therefore larger than L~13/12, and makes the scales strictly proper.
=== Pele temperament ===
In the [[pele]] temperament ([41 & 46 & 58]), following interpretations are available:
* L = 10/9, m = 21/20~22/21~256/243, s = 56/55~64/63~66/65~81/80;
* L = 11/10, m = 21/20~22/21~256/243, s = 40/39~45/44~50/49;
* L = 12/11, m = 21/20~22/21~256/243, s = 28/27~33/32~65/63;
* L = 13/12, m = 21/20~22/21~104/99~256/243, s = 27/26.
== External links ==
* [https://sw3.lumipakkanen.com/scale/XvmXDTFp0 5sRA Aeolian (46edo 7:3:1 Aberschismic chromedye)]
* [https://sw3.lumipakkanen.com/scale/Xvmsw1KBx 5sRA Aeolian (46edo 6:3:2 Parapyth chromedye)]


[[Category:Aberrismic theory]]
[[Category:Aberrismic theory]]
[[Category:Rank-3 scales]]
[[Category:Rank-3 scales]]