540edo: Difference between revisions
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{{ | {{ED intro}} | ||
== Theory == | == Theory == | ||
Since 540 = 2 × 270 and 540 = 45 × 12, | Since {{nowrap|540 {{=}} 2 × 270}} and {{nowrap|540 {{=}} 45 × 12}}, 540edo contains [[270edo]] and [[12edo]] as subsets, both being important [[zeta edo]]s. It is [[enfactoring|enfactored]] in the 13-limit, with the same tuning as 270edo, but it makes for a reasonable 17-, 19- and 23-limit system, and beyond. It is, however, no longer [[consistent]] in the [[15-odd-limit]], all because of [[15/13]] being 1.14 cents sharp of just. | ||
The equal temperament [[tempering out|tempers out]] [[1156/1155]] and [[2601/2600]] in the 17-limit; [[1216/1215]], [[1331/1330]], [[1445/1444]] and [[1729/1728]] in the 19-limit; [[1105/1104]] and [[1496/1495]] in the 23-limit. Although it does quite well in these limits, it is not as ''efficient'' as 270edo's original mappings, as it has greater relative errors (→ [[#Regular temperament properties]]). It is therefore a question of whether one thinks these tuning improvements and differently supplied [[essentially tempered chord]]s are worth the load of all the extra notes. | |||
The approximated [[29/1|29]] and [[31/1|31]] are relatively weak, but [[37/1|37]], [[41/1|41]] and [[43/1|43]] are quite spot on, with the 43 coming from 270edo. For this reason, we may consider it as a full [[43-limit]] system. For all the primes starting with 29, it removes the distinction of otonal and utonal [[superparticular ratio|superparticular]] pairs (e.g. 29/28 vs 30/29 for prime 29) by tempering out the corresponding [[square superparticular]]s, which is responsible for its slightly flat-tending tuning profile. Prime [[47/1|47]] does not have that privilege and falls practically halfway between, though the sharp mapping might be preferred to keep [[47/46]] wider than [[48/47]]. As a compensation, you do get a spot-on prime [[53/1|53]] for free. | |||
=== Prime harmonics === | === Prime harmonics === | ||
{{Harmonics in equal|540|columns= | {{Harmonics in equal|540|columns=12}} | ||
{{Harmonics in equal|540|columns=12|start=13|collapsed=true|title=Approximation of prime harmonics in 540edo (continued)}} | |||
=== Subsets and supersets === | |||
540 is a very composite number. The [[prime factorization]] of 540 is {{factorization|540}}. Its nontrivial divisors are {{EDOs| 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45, 54, 60, 90, 108, 135, 180, and 270 }}. | |||
A step of 540edo is known as a '''dexl''', proposed by [[Joseph Monzo]] in April 2023 as an [[interval size measure]]<ref>[http://tonalsoft.com/enc/d/dexl.aspx Tonalsoft Encyclopedia | Dexl / 540edo]</ref>. | |||
== | == Approximation to JI == | ||
540 | {{Q-odd-limit intervals|540|23}} | ||
== Regular temperament properties == | == Regular temperament properties == | ||
{| class="wikitable center-4 center-5 center-6" | {| class="wikitable center-4 center-5 center-6" | ||
! rowspan="2" | Subgroup | ! rowspan="2" | [[Subgroup]] | ||
! rowspan="2" | [[Comma list]] | ! rowspan="2" | [[Comma list|Comma List]] | ||
! rowspan="2" | [[Mapping]] | ! rowspan="2" | [[Mapping]] | ||
! rowspan="2" | Optimal<br>8ve | ! rowspan="2" | Optimal<br>8ve Stretch (¢) | ||
! colspan="2" | Tuning | ! colspan="2" | Tuning Error | ||
|- | |- | ||
! [[TE error|Absolute]] (¢) | ! [[TE error|Absolute]] (¢) | ||
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| 2.3.5.7.11.13.17 | | 2.3.5.7.11.13.17 | ||
| 676/675, 1001/1000, 1156/1155, 1716/1715, 3025/3024, 4096/4095 | | 676/675, 1001/1000, 1156/1155, 1716/1715, 3025/3024, 4096/4095 | ||
| | | {{mapping| 540 856 1254 1516 1868 1998 2207 }} | ||
| -0.0022 | | -0.0022 | ||
| 0.1144 | | 0.1144 | ||
Line 31: | Line 41: | ||
| 2.3.5.7.11.13.17.19 | | 2.3.5.7.11.13.17.19 | ||
| 676/675, 1001/1000, 1156/1155, 1216/1215, 1331/1330, 1445/1444, 1729/1728 | | 676/675, 1001/1000, 1156/1155, 1216/1215, 1331/1330, 1445/1444, 1729/1728 | ||
| | | {{mapping| 540 856 1254 1516 1868 1998 2207 2294 }} | ||
| -0.0098 | | -0.0098 | ||
| 0.1088 | | 0.1088 | ||
Line 38: | Line 48: | ||
| 2.3.5.7.11.13.17.19.23 | | 2.3.5.7.11.13.17.19.23 | ||
| 676/675, 1001/1000, 1105/1104, 1156/1155, 1216/1215, 1331/1330, 1445/1444, 1496/1495 | | 676/675, 1001/1000, 1105/1104, 1156/1155, 1216/1215, 1331/1330, 1445/1444, 1496/1495 | ||
| | | {{mapping| 540 856 1254 1516 1868 1998 2207 2294 2443 }} | ||
| -0.024 | | -0.024 | ||
| 0.1100 | | 0.1100 | ||
Line 44: | Line 54: | ||
|} | |} | ||
== Notes == |