468edo
468 equal divisions of the octave (abbreviated 468edo or 468ed2), also called 468-tone equal temperament (468tet) or 468 equal temperament (468et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 468 equal parts of about 2.56 ¢ each. Each step represents a frequency ratio of 21/468, or the 468th root of 2.
Theory
468edo is consistent to the 13-odd-limit with a sharp tuning tendency and a 2.3.7.13 subgroup inherited from 234edo.
As an equal temperament, it tempers out the undim comma and the ennealimma in the 5-limit; 2401/2400 and 4375/4374 in the 7-limit, supporting ennealimmal; 3025/3024 and 9801/9800 in the 11-limit, supporting hemiennealimmal; and 676/675, 1001/1000, 1716/1715, 2080/2079 in the 13-limit, supporting 13-limit hemiennealimmal. It also provides the optimal patent val for 13-limit unlit.
Odd harmonics
| Harmonic | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Absolute (¢) | +0.61 | +0.87 | +0.40 | +1.22 | -0.04 | +0.50 | -1.09 | +0.17 | -0.08 | +1.01 | -0.07 |
| Relative (%) | +23.8 | +33.8 | +15.8 | +47.5 | -1.4 | +19.4 | -42.5 | +6.7 | -3.0 | +39.5 | -2.7 | |
| Steps (reduced) |
742 (274) |
1087 (151) |
1314 (378) |
1484 (80) |
1619 (215) |
1732 (328) |
1828 (424) |
1913 (41) |
1988 (116) |
2056 (184) |
2117 (245) | |
Subsets and supersets
Since 468 factors into primes as 22 × 32 × 13, 468edo has subset edos 2, 3, 4, 6, 9, 12, 13, 18, 26, 36, 39, 52, 78, 117, 156, and 234.
Regular temperament properties
| Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
|---|---|---|---|---|---|
| Absolute (¢) | Relative (%) | ||||
| 2.3.5 | [41 -20 -4⟩, [1 -27 18⟩ | [⟨468 742 1087]] | −0.2524 | 0.1785 | 6.96 |
| 2.3.5.7 | 2401/2400, 4375/4374, [34 -14 -10 3⟩ | [⟨468 742 1087 1314]] | −0.2253 | 0.1615 | 6.30 |
| 2.3.5.7.11 | 2401/2400, 3025/3024, 4375/4374, 5767168/5740875 | [⟨468 742 1087 1314 1619]] | −0.1782 | 0.1725 | 6.73 |
| 2.3.5.7.11.13 | 676/675, 1001/1000, 1716/1715, 3025/3024, 495616/494325 | [⟨468 742 1087 1314 1619 1732]] | −0.1709 | 0.1583 | 6.17 |
| 2.3.5.7.11.13.17 | 676/675, 1001/1000, 1156/1155, 1716/1715, 3025/3024, 7616/7605 | [⟨468 742 1087 1314 1619 1732 1913]] | −0.1526 | 0.1533 | 5.98 |
Rank-2 temperaments
| Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
|---|---|---|---|---|
| 1 | 179\468 | 458.97 | 125/96 | Majvam |
| 4 | 194\468 (40\468) |
497.44 (102.56) |
4/3 (35/33) |
Unlit |
| 9 | 123\468 (19\468) |
315.38 (48.72) |
6/5 (36/35) |
Ennealimmal |
| 18 | 97\468 (7\468) |
248.72 (17.95) |
231/200 (99/98) |
Hemiennealimmal |
* Octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if distinct