Diasem: Difference between revisions
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'''Diasem''' is a 9-note [[Maximum variety|max-variety-3]], [[generator-offset]] scale with step pattern 5L 2M 2s, equivalent to the [[semiquartal]] ([[5L 4s]]) mos with two of the small steps made larger and the other two made smaller. Diasem is [[chiral]], with two rotationally non-equivalent variants: ''right-handed diasem'' LMLSLMLSL and ''left-handed diasem'' LSLMLSLML; these are mirror images. The fact that the small step of diatonic is made smaller results in [[26edo]] and [[31edo]] diasem having better melodic properties than the respective diatonic scales. The scale has two chains of fifth generators (with 5 notes and 4 notes, respectively) with offset a subminor third or a supermajor second. [[21edo]] is the smallest edo to support a non-degenerate diasem. | '''Diasem''' (also known as '''Tas''', from Archytas) is a 9-note [[Maximum variety|max-variety-3]], [[generator-offset]] scale with step pattern 5L 2M 2s, equivalent to the [[semiquartal]] ([[5L 4s]]) mos with two of the small steps made larger and the other two made smaller. Diasem is [[chiral]], with two rotationally non-equivalent variants: ''right-handed diasem'' LMLSLMLSL and ''left-handed diasem'' LSLMLSLML; these are mirror images. The fact that the small step of diatonic is made smaller results in [[26edo]] and [[31edo]] diasem having better melodic properties than the respective diatonic scales. The scale has two chains of fifth generators (with 5 notes and 4 notes, respectively) with offset a subminor third or a supermajor second. [[21edo]] is the smallest edo to support a non-degenerate diasem. | ||
Diasem can be tuned as a [[Just intonation subgroup|2.3.7 subgroup]] JI scale or a tempered version thereof, where L represents [[9/8]], M represents [[28/27]], and S represents [[64/63]]. | Diasem can be tuned as a [[Just intonation subgroup|2.3.7 subgroup]] JI scale or a tempered version thereof, where L represents [[9/8]], M represents [[28/27]], and S represents [[64/63]]. | ||
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[[File:Diasem Phrygian Example 31edo.mp3]] [[31edo]], L:M:S = 5:2:1 | [[File:Diasem Phrygian Example 31edo.mp3]] [[31edo]], L:M:S = 5:2:1 | ||
== | == Supersets == | ||
The diasem scale extends to a 14-note AG scale: LmLsLmLsL and LsLmLsLmL both extend to the scale mcmcmsmcmcmsmc (c = L − m), with two 7-note mosses generated by the diasem's fifths separated by m. This scale is not chiral. This scale extends diasem like how [[blackdye]] is a 10-note non-chiral AG extension of the [[Zarlino]] scale's AG pattern 3L 2m 2s, LmsLmLs. The 14-note extension is one of: | The diasem scale extends to a 14-note AG scale: LmLsLmLsL and LsLmLsLmL both extend to the scale mcmcmsmcmcmsmc (c = L − m), with two 7-note mosses generated by the diasem's fifths separated by m. This scale is not chiral. This scale extends diasem like how [[blackdye]] is a 10-note non-chiral AG extension of the [[Zarlino]] scale's AG pattern 3L 2m 2s, LmsLmLs. The 14-note extension is one of: | ||
* 5L 7m 2s (if m < c < L) | * 5L 7m 2s (if m < c < L) | ||
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5L 7m 2s must have a diatonic fifth, since L > 2m > m + s. The 31edo tuning (c = 3\31, m = 2\31, s = 1\31) of the scale is ideal for the 81/80-tempering 2.3.5.7 interpretation. | 5L 7m 2s must have a diatonic fifth, since L > 2m > m + s. The 31edo tuning (c = 3\31, m = 2\31, s = 1\31) of the scale is ideal for the 81/80-tempering 2.3.5.7 interpretation. | ||
Another | Another superset is scscsmscscsmsc, with c = L - s (5L 2m 7s if c > m). 31edo diasem yields 5L 2m 7s with step ratio 4:2:1. | ||
Both these tunings, 5L 7m 2s and 5L 2m 7s, have been named '''crossdye''' ("crossed eyes" referring to the two copies of 5L 2s diatonic + "blackdye", courtesy of [[User:CellularAutomaton|cellularAutomaton]]). 5L 7m 2s could be called ''chromatic crossdye'' and 5L 2m 7s could be called ''dietic crossdye''. | Both these tunings, 5L 7m 2s and 5L 2m 7s, have been named '''crossdye''' ("crossed eyes" referring to the two copies of 5L 2s diatonic + "blackdye", courtesy of [[User:CellularAutomaton|cellularAutomaton]]). 5L 7m 2s could be called ''chromatic crossdye'' and 5L 2m 7s could be called ''dietic crossdye''. | ||
2.3.7 JI diasem also has | |||
* a 19-note superset: mLsmsLmsmLsmsLmsmLs (5L 7m 7s), with L = 2187/2048, m = 28/27, and s = 64/63, | |||
* a 24-note superset: mLsmLmLsmLmLmsLmLmLsmLmLmsLmL (12L 12m 5s), with L = 28/27, s = 64/63, and s = 531441/524188. | |||
== See also == | == See also == |