40/39: Difference between revisions

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In [[13-limit]] [[just intonation]], '''40/39''' is the difference between the third octave of the third [[5/4]] ({{nowrap| 40 = 5 × 2<sup>3</sup> }}) and the fifth of the thirteenth partial of the same root ({{nowrap| 39 = 13 × 3 }}). Within an octave, it is the difference between [[39/32]] and [[5/4]] and thus between [[13/8]] and [[5/3]]. It is also the difference between the [[4/3|perfect fourth (4/3)]] and the [[13/10|tridecimal naiadic (13/10)]], and between the [[9/8|Pythagorean whole tone (9/8)]] and the [[15/13|tridecimal semifourth (15/13)]].  
In [[13-limit]] [[just intonation]], '''40/39''' is the difference between [[39/32]] and [[5/4]] and thus between [[13/8]] and [[5/3]]. It is also the difference between the [[4/3|perfect fourth (4/3)]] and the [[13/10|tridecimal naiadic (13/10)]], and between the [[9/8|Pythagorean whole tone (9/8)]] and the [[15/13|tridecimal semifourth (15/13)]].  


== Temperaments ==
== Temperaments ==
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* [[CWE]]: ~2 = 1200{{c}}, ~3/2 = 710.153{{c}}, ~5/4 = 383.023{{c}}
* [[CWE]]: ~2 = 1200{{c}}, ~3/2 = 710.153{{c}}, ~5/4 = 383.023{{c}}


[[Badness]] (Dirichlet): 0.227
[[Badness]] (Sintel): 0.227


== Notation ==
== Notation ==
=== Sagittal notation ===
=== Sagittal notation ===
In the [[Sagittal]] system, the downward version of this comma (possibly tempered) is represented (in a secondary role) by the sagittal {{sagittal | \\! }} and is called the '''13/5 small diesis''', or '''13/5S''' for short, because the simplest interval it notates is 13/5 (equiv. 13/10), as for example in C-F{{nbhsp}}{{sagittal | \\! }}. The primary role of {{ sagittal | \\! }} is [[6561/6400 #Sagittal notation|6400/6561]] (25S). The upward version is called '''5/13S''' or '''13/5S up''' and is represented (in a secondary role) by {{sagittal| //| }}.
In the [[Sagittal]] system, the downward version of this comma (possibly tempered) is represented (in a secondary role) by the sagittal {{sagittal | \\! }} and is called the '''13/5 small diesis''', or '''13/5S''' for short, because the simplest interval it notates is 13/5 (equiv. 13/10), as for example in C-F{{nbhsp}}{{sagittal | \\! }}. The primary role of {{ sagittal | \\! }} is [[6561/6400 #Sagittal notation|6400/6561]] (25S). The upward version is called '''5/13S''' or '''13/5S up''' and is represented (in a secondary role) by {{sagittal| //| }}.