401edo

 ← 400edo 401edo 402edo →
Prime factorization 401 (prime)
Step size 2.99252¢
Fifth 235\401 (703.242¢)
Semitones (A1:m2) 41:28 (122.7¢ : 83.79¢)
Dual sharp fifth 235\401 (703.242¢)
Dual flat fifth 234\401 (700.249¢)
Dual major 2nd 68\401 (203.491¢)
Consistency limit 3
Distinct consistency limit 3

401 equal divisions of the octave (abbreviated 401edo or 401ed2), also called 401-tone equal temperament (401tet) or 401 equal temperament (401et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 401 equal parts of about 2.99 ¢ each. Each step represents a frequency ratio of 21/401, or the 401st root of 2.

Theory

401edo is inconsistent to the 5-odd-limit and harmonic 3 is about halfway between its steps. Otherwise, it has a reasonable approximation to harmonics 5, 7, 9, 11, and 13, making it suitable for a 2.9.5.7.11.13 subgroup interpretation.

Using the patent val nonetheless, the equal temperament tempers out 283115520/282475249 and 703125/702464 in the 7-limit; 35156250/35153041, 2097152/2096325, 117649/117612, 226492416/226474325, 9765625/9732096, 42875/42768, 1375/1372, 5632/5625, 15488/15435, 202397184/201768035, 102487/102400 and 805255/802816 in the 11-limit. It provides the optimal patent val for diatessic, the 140 & 261 temperament.

Odd harmonics

Approximation of odd harmonics in 401edo
Harmonic 3 5 7 9 11 13 15 17 19 21 23
Error Absolute (¢) +1.29 -0.28 +0.75 -0.42 -0.69 +0.37 +1.01 -0.22 -1.25 -0.96 +0.15
Relative (%) +43.0 -9.3 +25.1 -14.0 -23.2 +12.4 +33.7 -7.3 -41.9 -31.9 +5.2
Steps
(reduced)
636
(235)
931
(129)
1126
(324)
1271
(68)
1387
(184)
1484
(281)
1567
(364)
1639
(35)
1703
(99)
1761
(157)
1814
(210)

Subsets and supersets

401edo is the 79th prime edo

Regular temperament properties

Subgroup Comma List Mapping Optimal
8ve Stretch (¢)
Tuning Error
Absolute (¢) Relative (%)
2.3 [636 -401 [401 636]] -0.4060 0.4058 13.56
2.3.5 15625/15552, [107 -66 -1 [401 636 931]] -0.2307 0.4139 13.83
2.3.5.7 10976/10935, 15625/15552, 67108864/66706983 [401 636 931 1126]] -0.2400 0.3588 11.99
2.3.5.7.11 2200/2187, 1375/1372, 5632/5625, 102487/102400 [401​ 636 ​931 ​1126 ​1387 ​]] -0.1518 0.3661 12.23
2.3.5.7.11.13 325/324, 352/351, 625/624, 1375/1372, 3276800/3270267 [401 ​636 ​931 ​1126 ​1387 ​1484]] -0.1431 0.3348 11.19

Rank-2 temperaments

Table of rank-2 temperaments by generator
Periods
per 8ve
Generator* Cents* Associated
Ratio*
Temperaments
1 169\401 505.74 75/56 Diatessic

* octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if it is distinct

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