13edt: Difference between revisions
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{{Infobox ET}} | |||
[[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 [[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]]. | |||
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 == | |||
{{Harmonics in equal|13|3|1|prec=2|intervals=odd}} | |||
{{Harmonics in equal|13|3|1|prec=2|intervals=odd|start=12}} | |||
* [[Relationship between Bohlen-Pierce and octave-ful temperaments]] | |||
== Intervals == | |||
{{Main|Intervals of BP}} | |||
{| class="wikitable center-all right-2 right-3" | |||
|- | |||
! Steps | |||
! [[Cent]]s | |||
! [[Hekt]]s | |||
! [[4L 5s (3/1-equivalent)|Enneatonic]]<br />degree | |||
! 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 | |||
| 146.3 | |||
| 100 | |||
| A1/m2 | |||
| [[49/45]] (−1.1{{c}}); [[27/25]] (+13.1{{c}}) | |||
| F | |||
|- | |||
| 2 | |||
| 292.6 | |||
| 200 | |||
| M2/d3 | |||
| [[25/21]] (−9.2{{c}}) | |||
| F#, Gb | |||
|- | |||
| 3 | |||
| 438.9 | |||
| 300 | |||
| A2/P3/d4 | |||
| [[9/7]] (+3.8{{c}}) | |||
| G | |||
|- | |||
| 4 | |||
| 585.2 | |||
| 400 | |||
| A3/m4/d5 | |||
| [[7/5]] (+2.7{{c}}) | |||
| H | |||
|- | |||
| 5 | |||
| 731.5 | |||
| 500 | |||
| M4/m5 | |||
| [[75/49]] (−5.4{{c}}) | |||
| H#, Jb | |||
|- | |||
| 6 | |||
| 877.8 | |||
| 600 | |||
| A4/M5 | |||
| [[5/3]] (−6.5{{c}}) | |||
| J | |||
|- | |||
| 7 | |||
| 1024.1 | |||
| 700 | |||
| A5/m6/d7 | |||
| [[9/5]] (+6.5{{c}}) | |||
| A | |||
|- | |||
| 8 | |||
| 1170.4 | |||
| 800 | |||
| M6/m7 | |||
| [[49/25]] (+5.4{{c}}) | |||
| A#, Bb | |||
|- | |||
| 9 | |||
| 1316.7 | |||
| 900 | |||
| A6/M7/d8 | |||
| [[15/7]] (−2.7{{c}}) | |||
| B | |||
|- | |||
| 10 | |||
| 1463.0 | |||
| 1000 | |||
| P8/d9 | |||
| [[7/3]] (−3.8{{c}}) | |||
| C | |||
|- | |||
| 11 | |||
| 1609.3 | |||
| 1100 | |||
| A8/m9 | |||
| [[63/25]] (+9.2{{c}}) | |||
| C#, Db | |||
|- | |||
| 12 | |||
| 1755.7 | |||
| 1200 | |||
| M9/d10 | |||
| [[135/49]] (+1.1{{c}}); [[25/9]] (−13.1{{c}}) | |||
| D | |||
|- | |||
| 13 | |||
| 1902.0 | |||
| 1300 | |||
| A9/P10 | |||
| [[3/1]] | |||
| E | |||
|} | |||
== JI approximation == | |||
[[File:13ed3-17-001.svg|alt=alt : Your browser has no SVG support.]] | |||
== 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 == | |||
* [[Bohlen-p_et]] | |||
* [[Catalog of 3.5.7 subgroup rank two temperaments]] | |||
* [[No-twos subgroup temperaments#3.5.7 subgroup temperaments]] | |||
* [[19ed5|19ED5]]: relative ED5 | |||
* [[23ed7|23ED7]]: relative ED7 | |||
[[Category:Tritave]] | |||
[[Category:Macrotonal]] | |||
[[Category:Nonoctave]] | |||
[[Category:Bohlen–Pierce]] | |||