444edo
| ← 443edo | 444edo | 445edo → |
444 equal divisions of the octave (abbreviated 444edo or 444ed2), also called 444-tone equal temperament (444tet) or 444 equal temperament (444et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 444 equal parts of about 2.7 ¢ each. Each step represents a frequency ratio of 21/444, or the 444th root of 2.
Theory
444edo is only consistent to the 5-odd-limit since harmonic 7 is about halfway between its steps. 444 = 4 × 111, and its harmonic 3 derives from 111edo. Using the patent val, the equal temperament tempers out 250047/250000, 29360128/29296875, 67108864/66976875 and in the 7-limit; 3025/3024, 5632/5625, 42592/42525, 102487/102400, 131072/130977, 160083/160000, 172032/171875, 322102/321489, 391314/390625 and 1771561/1769472 in the 11-limit. It supports the magnesium temperament.
Odd harmonics
| Harmonic | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Absolute (¢) | +0.75 | +0.17 | -1.26 | -1.21 | +0.03 | +0.01 | +0.92 | +0.45 | -0.22 | -0.51 | -1.25 |
| Relative (%) | +27.7 | +6.4 | -46.6 | -44.7 | +1.2 | +0.5 | +34.1 | +16.6 | -8.0 | -18.9 | -46.2 | |
| Steps (reduced) |
704 (260) |
1031 (143) |
1246 (358) |
1407 (75) |
1536 (204) |
1643 (311) |
1735 (403) |
1815 (39) |
1886 (110) |
1950 (174) |
2008 (232) | |
Subsets and supersets
Since 444 factors into 22 × 3 × 37, 444edo has subset edos 2, 3, 4, 6, 12, 37, 74, 111, 148, and 222. 1332edo, which triples it, gives a good correction to the harmonic 7.
Regular temperament properties
| Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
|---|---|---|---|---|---|
| Absolute (¢) | Relative (%) | ||||
| 2.3.5 | [41 -20 -4⟩, [-29 -11 20⟩ | [⟨444 704 1031]] | −0.1821 | 0.2071 | 7.66 |
Rank-2 temperaments
| Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
|---|---|---|---|---|
| 1 | 13\444 | 35.14 | 1990656/1953125 | Gammic (5-limit) |
| 4 | 184\444 (38\444) |
497.30 (102.70) |
4/3 (35/33) |
Undim (444d) |
* Octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if it is distinct