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Father–3 equivalence continuum: Difference between revisions

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The '''father–3 equivalence continuum''' is a [[equivalence continuum|continuum]] of [[5-limit]] [[regular temperament|temperaments]] which equate a number of [[16/15|classical diatonic semitones (16/15)]] with the [[32/27|Pythagorean minor third (32/27)]].
The '''father–3 equivalence continuum''' is a [[equivalence continuum|continuum]] of [[5-limit]] [[regular temperament|temperaments]] which equate a number of [[16/15|classical diatonic semitones (16/15)]] with the [[32/27|Pythagorean minor third (32/27)]].
Note that because 3et is a record equal temperament in the [[2.5 subgroup]], the continuum can be conceptualized as the [[Father–3 equivalence continuum/Godtone's approach|''augmented–dicot equivalence continuum'']], which Godtone argues is easier to understand, with characteristic 2.5-subgroup [[comma]] [[128/125]] as the interval with a single factor of 3 is [[25/24]].


All temperaments in the continuum satisfy {{nowrap|(16/15)<sup>''n''</sup> ~ 32/27}}. Varying ''n'' results in different temperaments listed in the table below. It converges to [[father]] as ''n'' approaches infinity. If we allow non-integer and infinite ''n'', the continuum describes the set of all [[5-limit]] temperaments supported by [[3edo]] due to it being the unique equal temperament that tempers both commas and thus tempers all combinations of them. The just value of ''n'' is approximately 2.63252…, and temperaments having ''n'' near this value tend to be the most accurate ones.  
All temperaments in the continuum satisfy {{nowrap|(16/15)<sup>''n''</sup> ~ 32/27}}. Varying ''n'' results in different temperaments listed in the table below. It converges to [[father]] as ''n'' approaches infinity. If we allow non-integer and infinite ''n'', the continuum describes the set of all [[5-limit]] temperaments supported by [[3edo]] due to it being the unique equal temperament that tempers both commas and thus tempers all combinations of them. The just value of ''n'' is approximately 2.63252…, and temperaments having ''n'' near this value tend to be the most accurate ones.  
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! ''n'' !! ''m''!! Temperament || Comma
! ''n'' !! ''m''!! Temperament || Comma
|-
|-
| 7/3 = 2.{{overline|3}} || 7/4 = 1.75 || [[Wesley]] || {{monzo| 13 2 -7 }}
| 7/3 = 2.{{overline|3}} || 7/4 = 1.75 || [[Wesley]] || {{monzo| -13 -2 7 }}
|-
| 5/2 = 2.5 || 5/3 = 1.{{overline|6}} || [[Magic]] || {{monzo| -10 -1 5 }}
|-
| 21/8 = 2.625 || 21/13 = 1.{{overline|615384}} || [[Mutt]] || {{monzo| -44 -3 21 }}
|-
|-
| 5/2 = 2.5 || 5/3 = 1.{{overline|6}} || [[Magic]] || {{monzo| 10 1 -5 }}
| 29/11 = 2.{{overline|63}} || 29/18 = 1.6{{overline|1}} || [[Squarschmidt]] || {{monzo| 61 4 -29 }}
|-
|-
| 8/3 = 2.{{overline|6}} || 8/5 = 1.6 || [[Würschmidt]] || {{monzo| 17 1 -8 }}
| 8/3 = 2.{{overline|6}} || 8/5 = 1.6 || [[Würschmidt]] || {{monzo| 17 1 -8 }}
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|}
|}


Because 3et is a record equal temperament in both 2.3 and [[2.5 subgroup]]s, there is another way to conceptualize this continuum. The characteristic 2.5-subgroup comma is [[128/125]], and the interval with a single factor of 3 is [[25/24]]. As such, Godtone has conceptualized this continuum as ''augmented–dicot equivalence continuum''. See [[{{PAGENAME}}/Godtone's approach]].
== Mutt (5-limit) ==
 
{{Main| Mutt }}
Others prefer conceptualizing this continuum in terms of {{nowrap| ''k'' {{=}} {{sfrac|1|''n'' − 2}} }} such that temperaments satisfy {{nowrap|(25/24)<sup>''k''</sup> {{=}} 16/15}}. This gives rise to the name ''chromatic–diatonic equivalence continuum'', where both ''chromatic'' and ''diatonic'' refer to the classical versions of semitones. The just value of ''k'' is approximately 1.58097…
: ''For extensions, see [[Horwell temperaments #Mutt]].''  
 
{| class="wikitable center-1"
|+ style="font-size: 105%;" | Temperaments with integer ''k''
|-
! rowspan="2" | ''k''
! rowspan="2" | Temperament
! colspan="2" | Comma
|-
! Ratio
! Monzo
|-
| -1
| [[Very low accuracy temperaments #Antonian|Antonian]]
| [[10/9]]
| {{Monzo| 1 -2 1 }}
|-
| 0
| [[Father]]
| [[16/15]]
| {{Monzo| 4 -1 -1 }}
|-
| 1
| [[Augmented (temperament)|Augmented]]
| [[128/125]]
| {{Monzo| 7 0 -3 }}
|-
| 2
| [[Magic]]
| [[3125/3072]]
| {{Monzo| 10 1 -5 }}
|-
| 3
| [[Wesley]]
| 78125/73728
| {{monzo| 13 2 -7 }}
|-
| 4
| 3 & 33c
| 1953125/1769472
| {{Monzo| 16 3 -9 }}
|-
| …
| …
| …
| …
|-
| ∞
| [[Dicot]]
| [[25/24]]
| {{Monzo| -3 -1 2 }}
|}
 
== 3 & 33c ==
This low-accuracy high-complexity temperament corresponds to {{nowrap| ''n'' {{=}} 9/4 }} and {{nowrap| ''m'' {{=}} 9/5 }}.


[[Subgroup]]: 2.3.5
[[Subgroup]]: 2.3.5


[[Comma list]]: 1953125/1769472
[[Comma list]]: {{monzo| -44 -3 21 }}


{{Mapping|legend=1| 3 2 6 | 0 3 1 }}
{{Mapping|legend=1| 3 -2 6 | 0 7 1 }}
: mapping generators: ~125/96, ~5/4
: mapping generators: ~98304/78125, ~5/4


[[Optimal tuning]]s:  
[[Optimal tuning]]s:  
* [[WE]]: ~125/96 = 401.2633{{c}}, ~5/4 = 367.0585{{c}} (~25/24 = 34.2047{{c}})
* [[WE]]: ~98304/78125 = 400.0227{{c}}, ~5/4 = 386.0017{{c}} (~393216/390625 = 14.0210{{c}})
: [[error map]]: {{val| +3.790 +1.747 -11.676 }}
: [[error map]]: {{val| +0.068 +0.012 -0.176 }}
* [[CWE]]: ~125/96 = 400.0000{{c}}, ~5/4 = 366.8103{{c}} (~25/24 = 33.1897{{c}})
* [[CWE]]: ~98304/78125 = 400.0000{{c}}, ~5/4 = 385.9858{{c}} (~393216/390625 = 14.0142{{c}})
: error map: {{val| 0.000 -1.524 -19.503 }}
: error map: {{val| 0.000 -0.055 -0.328 }}


{{Optimal ET sequence|legend=1| 3, …, 33c, 36c, 69cc }}
{{Optimal ET sequence|legend=1| 84, 87, 171, 771, 942, 1113, 1284, 1455, 4194cc, 5649cc }}


[[Badness]] (Sintel): 16.0
[[Badness]] (Sintel): 3.81


== Isnes ==
== Isnes ==
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[[Badness]] (Sintel): 30.4
[[Badness]] (Sintel): 30.4
== Squarschmidt (5-limit) ==
: ''For extensions, see [[Hemimage temperaments #Squarschmidt]].''
A generator for the squarschmidt temperament is the fourth root of [[5/2]], (5/2)<sup>1/4</sup>, tuned around 396.6 cents.
[[Subgroup]]: 2.3.5
[[Comma list]]: {{monzo| 61 4 -29 }}
{{Mapping|legend=1| 1 -8 1 | 0 29 4 }}
: mapping generators: ~2, ~98304/78125
[[Optimal tuning]]s:
* [[WE]]: ~2 = 1199.9653{{c}}, ~98304/78125 = 396.6094{{c}}
: [[error map]]: {{val| -0.099 +0.543 +0.029 -0.719 }}
* [[CWE]]: ~2 = 1200.0000{{c}}, ~98304/78125 = 396.6201{{c}}
: error map: {{val| 0.000 +0.653 +0.253 -0.552 }}
{{Optimal ET sequence|legend=1| 118, 593, 711, 829, 947, 9588cc, 10535cc, 11482ccc }}
[[Badness]] (Sintel): 5.12


[[Category:3edo]]
[[Category:3edo]]
[[Category:Equivalence continua]]
[[Category:Equivalence continua]]
Retrieved from "https://en.xen.wiki/w/Father–3_equivalence_continuum"