742edo: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
{{ | {{ED intro}} | ||
== Theory == | == Theory == | ||
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=== Prime harmonics === | === Prime harmonics === | ||
{{Harmonics in equal|742}} | {{Harmonics in equal|742|columns=11}} | ||
{{Harmonics in equal|742|columns=11|start=12|collapsed=1|title=Approximation of prime harmonics in 742edo (continued)}} | |||
=== Subsets and supersets === | === Subsets and supersets === | ||
| Line 17: | Line 18: | ||
! rowspan="2" | [[Comma list]] | ! rowspan="2" | [[Comma list]] | ||
! rowspan="2" | [[Mapping]] | ! rowspan="2" | [[Mapping]] | ||
! rowspan="2" | Optimal<br | ! rowspan="2" | Optimal<br>8ve stretch (¢) | ||
! colspan="2" | Tuning error | ! colspan="2" | Tuning error | ||
|- | |- | ||
| Line 24: | Line 25: | ||
|- | |- | ||
| 2.3.5 | | 2.3.5 | ||
| {{ | | {{Monzo| 23 6 -14 }}, {{monzo| -84 53 }} | ||
| {{ | | {{Mapping| 742 1176 1723 }} | ||
| −0.0157 | | −0.0157 | ||
| 0.0555 | | 0.0555 | ||
| Line 32: | Line 33: | ||
| 2.3.5.7 | | 2.3.5.7 | ||
| 2401/2400, 14348907/14336000, {{monzo| 23 6 -14 }} | | 2401/2400, 14348907/14336000, {{monzo| 23 6 -14 }} | ||
| {{ | | {{Mapping| 742 1176 1723 2083 }} | ||
| −0.0035 | | −0.0035 | ||
| 0.0525 | | 0.0525 | ||
| Line 39: | Line 40: | ||
| 2.3.5.7.11 | | 2.3.5.7.11 | ||
| 2401/2400, 9801/9800, 172032/171875, 1240029/1239040 | | 2401/2400, 9801/9800, 172032/171875, 1240029/1239040 | ||
| {{ | | {{Mapping| 742 1176 1723 2083 2567 }} | ||
| −0.0123 | | −0.0123 | ||
| 0.0501 | | 0.0501 | ||
| Line 46: | Line 47: | ||
| 2.3.5.7.11.13 | | 2.3.5.7.11.13 | ||
| 2401/2400, 4096/4095, 6656/6655, 9801/9800, 39366/39325 | | 2401/2400, 4096/4095, 6656/6655, 9801/9800, 39366/39325 | ||
| {{ | | {{Mapping| 742 1176 1723 2083 2567 2746 }} | ||
| −0.0302 | | −0.0302 | ||
| 0.0608 | | 0.0608 | ||
| Line 53: | Line 54: | ||
| 2.3.5.7.11.13.17 | | 2.3.5.7.11.13.17 | ||
| 1701/1700, 2058/2057, 2401/2400, 2601/2600, 4096/4095, 6656/6655 | | 1701/1700, 2058/2057, 2401/2400, 2601/2600, 4096/4095, 6656/6655 | ||
| {{ | | {{Mapping| 742 1176 1723 2083 2567 2746 3033 }} | ||
| −0.0317 | | −0.0317 | ||
| 0.0564 | | 0.0564 | ||
| Line 60: | Line 61: | ||
| 2.3.5.7.11.13.17.19 | | 2.3.5.7.11.13.17.19 | ||
| 1701/1700, 2058/2057, 2376/2375, 2401/2400, 2432/2431, 2601/2600, 3213/3211 | | 1701/1700, 2058/2057, 2376/2375, 2401/2400, 2432/2431, 2601/2600, 3213/3211 | ||
| {{ | | {{Mapping| 742 1176 1723 2083 2567 2746 3033 3152 }} | ||
| −0.0295 | | −0.0295 | ||
| 0.0531 | | 0.0531 | ||
| Line 67: | Line 68: | ||
| 2.3.5.7.11.13.17.19.23 | | 2.3.5.7.11.13.17.19.23 | ||
| 1197/1196, 1496/1495, 1701/1700, 2025/2024, 2058/2057, 2401/2400, 2601/2600, 3213/3211 | | 1197/1196, 1496/1495, 1701/1700, 2025/2024, 2058/2057, 2401/2400, 2601/2600, 3213/3211 | ||
| {{ | | {{Mapping| 742 1176 1723 2083 2567 2746 3033 3152 3357 }} (742i) | ||
| −0.0468 | | −0.0468 | ||
| 0.0699 | | 0.0699 | ||
| Line 79: | Line 80: | ||
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | |+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | ||
|- | |- | ||
! Periods<br | ! Periods<br>per 8ve | ||
! Generator* | ! Generator* | ||
! Cents* | ! Cents* | ||
! Associated<br | ! Associated<br>ratio* | ||
! Temperaments | ! Temperaments | ||
|- | |- | ||
| Line 90: | Line 91: | ||
| 8388608/7381125 | | 8388608/7381125 | ||
| [[Fortune]] | | [[Fortune]] | ||
|- | |||
| 1 | |||
| 243\742 | |||
| 392.992 | |||
| 2744/2187 | |||
| [[Emmthird]] (7-limit) | |||
|- | |- | ||
| 1 | | 1 | ||
| Line 104: | Line 111: | ||
|- | |- | ||
| 14 | | 14 | ||
| 434\742<br | | 434\742<br>(10\742) | ||
| 701.886<br | | 701.886<br>(16.173) | ||
| 3/2<br | | 3/2<br>(105/104) | ||
| [[Silicon]] | | [[Silicon]] | ||
|- | |- | ||
| 53 | | 53 | ||
| 239\742<br | | 239\742<br>(1\742) | ||
| 386.523<br | | 386.523<br>(1.617) | ||
| 5/4<br | | 5/4<br>(32805/32768) | ||
| [[Mercator]] | | [[Mercator]] | ||
|- | |- | ||
| 53 | | 53 | ||
| 565\742<br | | 565\742<br>(5\742) | ||
| 913.746<br | | 913.746<br>(8.086) | ||
| 441/260<br | | 441/260<br>(196/195) | ||
| [[Iodine]] | | [[Iodine]] | ||
|} | |} | ||
<nowiki />* [[Normal | <nowiki/>* [[Normal forms #Equave-reduced-generator form|Octave-reduced form]], reduced to the first half-octave, and [[normal forms #Minimal-generator form|minimal form]] in parentheses if distinct | ||
== Scales == | |||
* Silicon[28]: 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 | |||
Latest revision as of 22:24, 25 April 2026
| ← 741edo | 742edo | 743edo → |
742 equal divisions of the octave (abbreviated 742edo or 742ed2), also called 742-tone equal temperament (742tet) or 742 equal temperament (742et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 742 equal parts of about 1.62 ¢ each. Each step represents a frequency ratio of 21/742, or the 742nd root of 2.
Theory
742edo is a very strong 19-limit system and a zeta peak edo, and is distinctly consistent in the 21-odd-limit. As an equal temperament, it tempers out the vishnuzma and the fortune comma in the 5-limit, supporting vishnu and fortune; 2401/2400 in the 7-limit, 9801/9800 in the 11-limit, 4096/4095, 6656/6655, 10648/10647 in the 13-limit, 1701/1700, 2058/2057, 2601/2600, 4914/4913, 5832/5831 in the 17-limit, 2376/2375, 2432/2431, 2926/2925, 3136/3135, 4200/4199, 5776/5775, 5929/5928, 5985/5984, 6860/6859 in the 19-limit.
Prime harmonics
| Harmonic | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Absolute (¢) | +0.000 | -0.068 | +0.209 | -0.093 | +0.165 | +0.443 | +0.166 | +0.061 | -0.781 | +0.611 | -0.022 |
| Relative (%) | +0.0 | -4.2 | +12.9 | -5.7 | +10.2 | +27.4 | +10.3 | +3.8 | -48.3 | +37.8 | -1.4 | |
| Steps (reduced) |
742 (0) |
1176 (434) |
1723 (239) |
2083 (599) |
2567 (341) |
2746 (520) |
3033 (65) |
3152 (184) |
3356 (388) |
3605 (637) |
3676 (708) | |
| Harmonic | 37 | 41 | 43 | 47 | 53 | 59 | 61 | 67 | 71 | 73 | 79 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Absolute (¢) | -0.670 | -0.491 | -0.466 | +0.801 | -0.189 | +0.128 | +0.635 | -0.062 | -0.182 | +0.243 | -0.655 |
| Relative (%) | -41.4 | -30.4 | -28.8 | +49.5 | -11.7 | +7.9 | +39.3 | -3.8 | -11.2 | +15.0 | -40.5 | |
| Steps (reduced) |
3865 (155) |
3975 (265) |
4026 (316) |
4122 (412) |
4250 (540) |
4365 (655) |
4401 (691) |
4501 (49) |
4563 (111) |
4593 (141) |
4677 (225) | |
Subsets and supersets
Since 742 factors into 2 × 7 × 53, 742edo has subset edos 2, 7, 14, 53, 106, and 371, of which 7edo, 14edo and 53edo are very notable. It supports silicon (224 & 518) with 14 periods per octave in the 13-limit, and iodine (159& 583f) with 53 periods per octave in the 17-limit.
Regular temperament properties
| Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
|---|---|---|---|---|---|
| Absolute (¢) | Relative (%) | ||||
| 2.3.5 | [23 6 -14⟩, [-84 53⟩ | [⟨742 1176 1723]] | −0.0157 | 0.0555 | 3.43 |
| 2.3.5.7 | 2401/2400, 14348907/14336000, [23 6 -14⟩ | [⟨742 1176 1723 2083]] | −0.0035 | 0.0525 | 3.24 |
| 2.3.5.7.11 | 2401/2400, 9801/9800, 172032/171875, 1240029/1239040 | [⟨742 1176 1723 2083 2567]] | −0.0123 | 0.0501 | 3.10 |
| 2.3.5.7.11.13 | 2401/2400, 4096/4095, 6656/6655, 9801/9800, 39366/39325 | [⟨742 1176 1723 2083 2567 2746]] | −0.0302 | 0.0608 | 3.76 |
| 2.3.5.7.11.13.17 | 1701/1700, 2058/2057, 2401/2400, 2601/2600, 4096/4095, 6656/6655 | [⟨742 1176 1723 2083 2567 2746 3033]] | −0.0317 | 0.0564 | 3.49 |
| 2.3.5.7.11.13.17.19 | 1701/1700, 2058/2057, 2376/2375, 2401/2400, 2432/2431, 2601/2600, 3213/3211 | [⟨742 1176 1723 2083 2567 2746 3033 3152]] | −0.0295 | 0.0531 | 3.28 |
| 2.3.5.7.11.13.17.19.23 | 1197/1196, 1496/1495, 1701/1700, 2025/2024, 2058/2057, 2401/2400, 2601/2600, 3213/3211 | [⟨742 1176 1723 2083 2567 2746 3033 3152 3357]] (742i) | −0.0468 | 0.0699 | 4.32 |
- 742et has a lower 19-limit relative error than any previous equal temperaments. It is only bettered by 935 in terms of absolute error, and by 1178 in terms of relative error.
- 742et (742i val) is also notable in the 17- and 23-limit, where it has lower absolute errors than any previous equal temperaments. In the 17-limit it beats 581 and is bettered by 764; in the 23-limit it beats 718 and is bettered by 814.
Rank-2 temperaments
| Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
|---|---|---|---|---|
| 1 | 137\742 | 221.563 | 8388608/7381125 | Fortune |
| 1 | 243\742 | 392.992 | 2744/2187 | Emmthird (7-limit) |
| 1 | 303\742 | 490.026 | 896/675 | Surmarvelpyth |
| 2 | 44\742 | 71.159 | 25/24 | Vishnu |
| 14 | 434\742 (10\742) |
701.886 (16.173) |
3/2 (105/104) |
Silicon |
| 53 | 239\742 (1\742) |
386.523 (1.617) |
5/4 (32805/32768) |
Mercator |
| 53 | 565\742 (5\742) |
913.746 (8.086) |
441/260 (196/195) |
Iodine |
* Octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if distinct
Scales
- Silicon[28]: 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43 10 43