Duodene: Difference between revisions

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As a lattice structure, it consists of a chain of three [[3/2|perfect fifths]] ({{dash|F, C, G, D}}) with [[5/4|just major thirds]] above and below each of these.<ref>[http://www.tonalsoft.com/enc/d/duodene.aspx duodene] in the Tonalsoft Encyclopedia of Microtonal Music Theory</ref>

When arranged on a standard [[Halberstadt keyboard|piano keyboard]], the white keys of a duodene form a just diatonic scale, specifically [[Ptolemy's intense diatonic]] scale.

~~The duodene can be understood as a [[detempering]] of both [[12edo]] and the [[meantone]] [[7L 5s|chromatic scale]].~~

It can be constructed as a [[Fokker block]] with the [[81/80|syntonic comma]] (81/80) and the [[128/125|enharmonic diesis]] (128/125) as chromas.

It is also an [[Euler-Fokker genus]] of <math>675 = 3^3 \times 5^3</math>, meaning it comprises all divisors of 675, reduced by octave equivalence.

It is also an [[Euler-Fokker genus]] of <math>675 = 3^3 \times 5^2</math>, meaning it comprises all divisors of 675, reduced by octave equivalence.

In Indian musical traditions, it is known as "Gandhar tuning."{{citation needed}}

=== As a detempering ===

Duodene can be tempered to several scales, which it can itself be understood as a detempering of.

==== Augmented diesis ====

If the augmented diesis is tempered out (as in 15edo), the MOS scale [[3L 9s]] is obtained, where the large step represents 27/25 and 135/128, and the small step represents 16/15 and 25/24. This is one possible 12-note chromatic in [[augmented temperament]].

==== Syntonic comma ====

If the syntonic comma is tempered out (as in 19edo), the MOS scale [[7L 5s]] is obtained, where the large step represents 27/25 and 16/15, and the small step represents 135/128 and 25/24. This is the 12-note chromatic of [[meantone temperament]].

If both chromas are tempered out, the result is 12-tone equal temperament (or an enfactoring, like [[24edo]]).

== Step pattern ==

Duodene is a tuning of the MV4 step pattern MnMsMnMMsLsM, which has 1 large step (27/25), 6 medium steps (16/15), 2 narrow steps (135/128), and 3 small steps (25/24). It can be represented in any edo which represents both the syntonic comma and the augmented diesis. The simplest tuning of this pattern is 29edo (s = 1, n = 2, M = 3, L = 4), but better tunings include 41edo and 53edo. In [[schismic]] temperament (which equates the augmented diesis and two syntonic commas), the sizes of the steps are equidistant.

== Scala file ==

<pre>

<pre>! duodene.scl

! duodene.scl

!

Ellis's Duodene

Line 38:

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9/5

15/8

2/1

2/1</pre>

</pre>

== Music ==

@@ Line 11: / Line 11: @@
 As a lattice structure, it consists of a chain of three [[3/2|perfect fifths]] ({{dash|F, C, G, D}}) with [[5/4|just major thirds]] above and below each of these.<ref>[http://www.tonalsoft.com/enc/d/duodene.aspx duodene] in the Tonalsoft Encyclopedia of Microtonal Music Theory</ref>
 When arranged on a standard [[Halberstadt keyboard|piano keyboard]], the white keys of a duodene form a just diatonic scale, specifically [[Ptolemy's intense diatonic]] scale.
-The duodene can be understood as a [[detempering]] of both [[12edo]] and the [[meantone]] [[7L 5s|chromatic scale]].
 It can be constructed as a [[Fokker block]] with the [[81/80|syntonic comma]] (81/80) and the [[128/125|enharmonic diesis]] (128/125) as chromas.
-It is also an [[Euler-Fokker genus]] of <math>675 = 3^3 \times 5^3</math>, meaning it comprises all divisors of 675, reduced by octave equivalence.
+It is also an [[Euler-Fokker genus]] of <math>675 = 3^3 \times 5^2</math>, meaning it comprises all divisors of 675, reduced by octave equivalence.
 In Indian musical traditions, it is known as "Gandhar tuning."{{citation needed}}
+=== As a detempering ===
+Duodene can be tempered to several scales, which it can itself be understood as a detempering of.
+==== Augmented diesis ====
+If the augmented diesis is tempered out (as in 15edo), the MOS scale [[3L 9s]] is obtained, where the large step represents 27/25 and 135/128, and the small step represents 16/15 and 25/24. This is one possible 12-note chromatic in [[augmented temperament]].
+==== Syntonic comma ====
+If the syntonic comma is tempered out (as in 19edo), the MOS scale [[7L 5s]] is obtained, where the large step represents 27/25 and 16/15, and the small step represents 135/128 and 25/24. This is the 12-note chromatic of [[meantone temperament]].
+If both chromas are tempered out, the result is 12-tone equal temperament (or an enfactoring, like [[24edo]]).
+== Step pattern ==
+Duodene is a tuning of the MV4 step pattern MnMsMnMMsLsM, which has 1 large step (27/25), 6 medium steps (16/15), 2 narrow steps (135/128), and 3 small steps (25/24). It can be represented in any edo which represents both the syntonic comma and the augmented diesis. The simplest tuning of this pattern is 29edo (s = 1, n = 2, M = 3, L = 4), but better tunings include 41edo and 53edo. In [[schismic]] temperament (which equates the augmented diesis and two syntonic commas), the sizes of the steps are equidistant.
 == Scala file ==
-<pre>
+<pre>! duodene.scl
-! duodene.scl
 !
 Ellis's Duodene
@@ Line 38: / Line 49: @@
 /5
 /8
-/1
+/1</pre>
-</pre>
 == Music ==