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{{Infobox ET}} | {{Infobox ET}} | ||
[[File:13edt.png|thumb|alt=13edt.png|A plot of the [[ | [[File:13edt.png|thumb|alt=13edt.png|A plot of the [[the Riemann zeta function and tuning#Removing primes|no-twos Z-function]], in terms of which 13edt is the fourth no-twos zeta peak [[EDT]].]] | ||
'''13 equal divisions of the tritave''' ('''13edt''') is the [[nonoctave]] [[tuning system]] derived by dividing the [[tritave]] (3/1) into 13 equal steps of 146.3 [[cent]]s each, or the thirteenth root of 3. It is best known as the equal-tempered version of the [[ | '''13 equal divisions of the tritave''' ('''13edt''') is the [[nonoctave]] [[tuning system]] derived by dividing the [[tritave]] (3/1) into 13 equal steps of 146.3 [[cent]]s each, or the thirteenth root of 3. It is best known as the equal-tempered version of the [[Bohlen–Pierce]] scale, and therefore has received by far the most attention among equal divisions of the tritave. | ||
It provides an excellent approximation to the [[3.5.7 subgroup]], especially for its size, being comparable to [[34edo]]'s accuracy in the 5-limit. In this subgroup, it tempers out [[245/243]] and [[3125/3087]], the same commas as [[Sensamagic_clan#Bohpier|bohpier temperament]]. It is less impressive in higher prime limits, but makes for excellent no-twos 7-limit harmony. For higher limits, the multiples of 13 ([[26edt]], [[39edt]], and [[52edt]]) come to the fore. | |||
13edt can be described as approximately 8.202[[edo]]. This implies that each step of 13edt can be approximated by 5 steps of [[41edo]]. | 13edt can be described as approximately 8.202[[edo]]. This implies that each step of 13edt can be approximated by 5 steps of [[41edo]]. | ||
In the | In the [[no-2]] [[3/1]]-[[equave]]-[[7-limit]], [[13edt]] maintains the smallest relative error of any EDT until [[258edt]] and [[271edt]], and the smallest absolute error until [[56edt]]. | ||
== Theory == | == Theory == | ||
{ | {{Harmonics in equal|13|3|1|prec=2|intervals=odd}} | ||
{{Harmonics in equal|13|3|1|prec=2|intervals=odd|start=12}} | |||
| | |||
| | |||
| 13 | |||
| | |||
| | |||
| | |||
|} | |||
* [[Relationship between Bohlen-Pierce and octave-ful temperaments]] | * [[Relationship between Bohlen-Pierce and octave-ful temperaments]] | ||
| Line 68: | Line 19: | ||
{{Main|Intervals of BP}} | {{Main|Intervals of BP}} | ||
{| class="wikitable center- | {| class="wikitable center-all right-2 right-3" | ||
|- | |- | ||
! Steps | ! Steps | ||
! [[Cent]]s | ! [[Cent]]s | ||
! [[Hekt]]s | ! [[Hekt]]s | ||
! | ! [[4L 5s (3/1-equivalent)|Enneatonic]]<br />degree | ||
! Corresponding | ! Corresponding<br />3.5.7 subgroup<br />intervals | ||
! [[Lambda ups and downs notation|Lambda]]<br />(sLsLsLsLs, {{nowrap|E {{=}} 1/1}}) | |||
|- | |||
! [[ | | 0 | ||
| 0 | |||
| 0 | |||
| P1 | |||
| 1/1 | |||
| E | |||
|- | |- | ||
| 1 | | 1 | ||
| Line 83: | Line 39: | ||
| 100 | | 100 | ||
| A1/m2 | | A1/m2 | ||
| 27/25 | | [[49/45]] (−1.1{{c}}); [[27/25]] (+13.1{{c}}) | ||
| F | |||
| | |||
|- | |- | ||
| 2 | | 2 | ||
| Line 92: | Line 46: | ||
| 200 | | 200 | ||
| M2/d3 | | M2/d3 | ||
| 25/21 | | [[25/21]] (−9.2{{c}}) | ||
| F#, Gb | |||
| | |||
|- | |- | ||
| 3 | | 3 | ||
| Line 101: | Line 53: | ||
| 300 | | 300 | ||
| A2/P3/d4 | | A2/P3/d4 | ||
| 9/7 | | [[9/7]] (+3.8{{c}}) | ||
| G | |||
| | |||
|- | |- | ||
| 4 | | 4 | ||
| Line 110: | Line 60: | ||
| 400 | | 400 | ||
| A3/m4/d5 | | A3/m4/d5 | ||
| 7/5 | | [[7/5]] (+2.7{{c}}) | ||
| H | |||
| | |||
|- | |- | ||
| 5 | | 5 | ||
| Line 119: | Line 67: | ||
| 500 | | 500 | ||
| M4/m5 | | M4/m5 | ||
| 75/49 | | [[75/49]] (−5.4{{c}}) | ||
| | | H#, Jb | ||
|- | |- | ||
| 6 | | 6 | ||
| Line 128: | Line 74: | ||
| 600 | | 600 | ||
| A4/M5 | | A4/M5 | ||
| 5/3 | | [[5/3]] (−6.5{{c}}) | ||
| J | |||
| | |||
|- | |- | ||
| 7 | | 7 | ||
| Line 137: | Line 81: | ||
| 700 | | 700 | ||
| A5/m6/d7 | | A5/m6/d7 | ||
| 9/5 | | [[9/5]] (+6.5{{c}}) | ||
| | | A | ||
|- | |- | ||
| 8 | | 8 | ||
| Line 146: | Line 88: | ||
| 800 | | 800 | ||
| M6/m7 | | M6/m7 | ||
| 49/25 | | [[49/25]] (+5.4{{c}}) | ||
| | | A#, Bb | ||
|- | |- | ||
| 9 | | 9 | ||
| Line 155: | Line 95: | ||
| 900 | | 900 | ||
| A6/M7/d8 | | A6/M7/d8 | ||
| 15/7 | | [[15/7]] (−2.7{{c}}) | ||
| | | B | ||
|- | |- | ||
| 10 | | 10 | ||
| Line 164: | Line 102: | ||
| 1000 | | 1000 | ||
| P8/d9 | | P8/d9 | ||
| 7/3 | | [[7/3]] (−3.8{{c}}) | ||
| | | C | ||
|- | |- | ||
| 11 | | 11 | ||
| Line 173: | Line 109: | ||
| 1100 | | 1100 | ||
| A8/m9 | | A8/m9 | ||
| 63/25 | | [[63/25]] (+9.2{{c}}) | ||
| | | C#, Db | ||
|- | |- | ||
| 12 | | 12 | ||
| Line 182: | Line 116: | ||
| 1200 | | 1200 | ||
| M9/d10 | | M9/d10 | ||
| 25/9 | | [[135/49]] (+1.1{{c}}); [[25/9]] (−13.1{{c}}) | ||
| D | |||
| | |||
|- | |- | ||
| 13 | | 13 | ||
| Line 191: | Line 123: | ||
| 1300 | | 1300 | ||
| A9/P10 | | A9/P10 | ||
| 3/1 | | [[3/1]] | ||
| | | E | ||
|} | |} | ||
| Line 201: | Line 131: | ||
== Regular temperament properties == | == Regular temperament properties == | ||
{{ | {| class="wikitable center-4 center-5 center-6" | ||
! rowspan="2" | Subgroup | |||
! rowspan="2" | [[Comma list]] | |||
! rowspan="2" | [[Mapping]] | |||
! rowspan="2" | Optimal<br>Equave stretch (¢) | |||
! colspan="2" | Tuning error | |||
|- | |||
! [[TE error|Absolute]] (¢) | |||
! [[TE simple badness|Relative]] (%) | |||
|- | |||
| 3.5.7 | |||
| 245/243, 3125/3087 | |||
| [{{val| 13 19 23 }}] (b13) | |||
| +1.393 | |||
| 1.150 | |||
| 0.79 | |||
|} | |||
=== Rank-2 temperaments === | |||
{| class="wikitable center-all right-3 left-5" | |||
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | |||
|- | |||
! Periods<br />per tritave | |||
! Generator<br />(reduced) | |||
! Cents<br />(reduced) | |||
! Associated<br />ratio | |||
! Temperament | |||
|- | |||
| 1 | |||
| 1\13 | |||
| 146.30 | |||
| 49/45 | |||
| [[Procyon]] | |||
|- | |||
| 1 | |||
| 2\13 | |||
| 292.61 | |||
| 25/21 | |||
| [[Sirius]] | |||
|- | |||
| 1 | |||
| 3\13 | |||
| 438.91 | |||
| 9/7 | |||
| [[BPS]] | |||
|- | |||
| 1 | |||
| 4\13 | |||
| 585.22 | |||
| 7/5 | |||
| [[Canopus]] | |||
|- | |||
| 1 | |||
| 5\13 | |||
| 731.63 | |||
| 75/49 | |||
| | |||
|- | |||
| 1 | |||
| 6\13 | |||
| 877.83 | |||
| 5/3 | |||
| [[Arcturus]] | |||
|} | |||
== See also == | == See also == | ||
* [[Bohlen-p_et]] | * [[Bohlen-p_et]] | ||
* [[Catalog of 3.5.7 subgroup rank two temperaments]] | * [[Catalog of 3.5.7 subgroup rank two temperaments]] | ||
* [[No-twos subgroup temperaments#3.5.7 subgroup temperaments]] | |||
* [[19ed5|19ED5]]: relative ED5 | * [[19ed5|19ED5]]: relative ED5 | ||
* [[23ed7|23ED7]]: relative ED7 | * [[23ed7|23ED7]]: relative ED7 | ||
[[Category:Tritave]] | [[Category:Tritave]] | ||
[[Category:Macrotonal]] | [[Category:Macrotonal]] | ||
[[Category:Nonoctave]] | [[Category:Nonoctave]] | ||
[[Category: | [[Category:Bohlen–Pierce]] | ||