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In [[aberrismic theory]], '''diachrome''' (also denoted 5s) is a set of three 5L2m5s 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.
 
''Diachrome'' is named from ''diatonic'' and ''chromatic'' for the [[5L 7s]] and [[7L 5s]] children of [[5L 2s]] that the L = m and m = s tunings reflect.


''Diachrome'' is named from ''diatonic'' and ''chromatic'' for the [[5L 7s|5L7s]] and [[7L 5s|7L5s]] children of [[5L2s]] that the L=m and m=s tunings reflect.
== Structure ==
== Structure ==
5sC has two chains of "fifths" 3L + m + 3s both having 6 notes and offset by 3L + m + 2s. The three leftmost notes of the lower chain (the one not offset by 3L + m + 2s) are joined to the three rightmost notes of the upper chain by 2L + m. 5sL (resp. 5sR) similarly has two chains of fifths, but the lower chain has 7 (resp. 5) notes and the upper chain 5 (resp. 7) notes.
=== Lattice ===
5sC has two chains of "fifths" (the 7-step 3L + m + 3s) both having 6 notes and offset by 3L + m + 2s. The interval L + s is thus reached by stacking two fifths and reducing, and m is reached by stacking -5 fifths and reducing. The three leftmost notes of the lower chain (the one not offset by 3L + m + 2s) are joined to the three rightmost notes of the upper chain by 2L + m. 5sL (resp. 5sR) similarly has two chains of fifths, but the lower chain has 7 (resp. 5) notes and the upper chain 5 (resp. 7) notes.
 
=== As substitution scale ===
In terms of [[MOS substitution|substitution]], 5sL = subst('''XXXXXXmXXXXm''', '''X''', '''Ls'''), 5sR = subst('''XXXXXXmXXXXm''', '''X''', '''sL'''), and 5sC = subst('''XXXXXmXXXXXm''', '''X''', '''Ls'''). (See [[User:Inthar/Notation]] for the explanation of this notation.)
 
=== Balance ===
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 is available in good RTT edos that have quasi-just or Parapyth fifths.
 
The first edos with a diachrome tuning are {{EDOs|24, 29, 31, 34, 36, 38, 39, 41, 43, 44, 45, 46, 48}}.
 
== Temperament interpretations ==
== Temperament interpretations ==
Diachrome is most accurate to JI in tunings that have quasi-just or Parapyth fifths. In both 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] ===
 
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:
=== 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 5.8{{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.


=== 2.3.7.11.13 Parapyth ===
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.
Diachrome can be given a [[Parapyth]] (2.3.7.11.13[29 & 41 & 46]) tempering:
 
* The L step becomes 12/11
=== 2.3.7.11.13 parapyth ===
* The m step becomes 256/243~22/21~104/99
Diachrome can be given a [[parapyth]] (2.3.7.11.13[29 & 41 & 46]) tempering:
* The s step becomes 28/27~33/32
* The L step becomes 12/11;
* The m step becomes 22/21~104/99~256/243;
* 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,
Line 30: Line 49:
* 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 '''ms''' 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]".
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]".
 
=== 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 m step is 256/243~128/121~93/88~19/18;
* The s step is 33/32~32/31~95/92.
 
The tempered tuning thus has the mappings
* 3/2 = 3L + m + 3s,
* 11/8 = 3L + 2s = 2L + m + 3s,
* 19/16 = L + m + s,
* 23/20 = L + m,
* 31/16 = 5L + 2m + 4s.
 
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] ===
A diachrome is also available in the 2.3.7.13.19.23[17 & 19 & 41] tempering:
* The L step is 13/12;
* The m step is 256/243~96/91~19/18;
* The s step is 28/27~27/26.
 
The tempered tuning has the mappings
* 3/2 = 3L + m + 3s,
* 7/4 = 4L + m + 5s,
* 13/8 = 4L + m + 3s,
* 19/16 = L + m + s,
* 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.
 
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:Rank-3 scales]]
[[Category:Aberrismic theory]]
[[Category:Rank-3 scales]]