256edo: Difference between revisions

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{{Infobox ET}}
{{Infobox ET}}
{{EDO intro|256}}
{{ED intro}}
== Theory ==
{{harmonics in equal|256}}
256edo is [[contorted]] in the 5-limit, and the error of harmonic 7 leads to inconsistency, which is likely one of the reasons this EDO attracts little interest. 256edo is good at the 2.23.43.47 subgroup. If the error below 40% is considered "good", 256edo can be used to play no-fives 17 limit. 


256edo can also be played using non-contorted harmonics, no matter how bad the approximation. Under such rule, 256edo supports the 2.7.13.19 subgroup. In the 2.7.13.19 subgroup in the patent val, 256edo tempers out 32851/32768, and [[support]]s the corresponding 20 & 73 & 256 rank 3 temperament.  
256edo is [[enfactoring|enfactored]] in the [[5-limit]] with the same tuning as [[128edo]], and the error of [[harmonic]] [[7/1|7]] leads to in[[consistency]], which is likely one of the reasons this edo attracts little interest. To start with, consider the sharp-tending 256c [[val]] {{val| 256 406 '''595''' 719 886 }}, which [[tempering out|tempers out]] [[2401/2400]], [[3388/3375]], [[5120/5103]], so that it [[support]]s 7-limit [[hemififths]] and [[11-limit]] [[semihemi]]. The [[patent val]] {{val| 256 406 '''594''' 719 886 }} tempers out [[540/539]], 2200/2187, [[4000/3969]], 12005/11979, among others. It is best tuned in the 2.3.7.11 [[subgroup]], in which it is consistent to the [[11-odd-limit]] minus intervals involving [[5/1|5]].  


[[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->
In the higher limits, it approximates harmonics 23, 43, and 47 quite accurately.
 
=== Odd harmonics ===
{{Harmonics in equal|256}}
 
=== Subsets and supersets ===
Since 256 factors into {{factorization|256}}, 256edo has subset edos {{EDOs| 2, 4, 8, 16, 32, 64, and 128 }}.

Latest revision as of 17:11, 20 February 2025

← 255edo 256edo 257edo →
Prime factorization 28
Step size 4.6875 ¢ 
Fifth 150\256 (703.125 ¢) (→ 75\128)
Semitones (A1:m2) 26:18 (121.9 ¢ : 84.38 ¢)
Consistency limit 3
Distinct consistency limit 3

256 equal divisions of the octave (abbreviated 256edo or 256ed2), also called 256-tone equal temperament (256tet) or 256 equal temperament (256et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 256 equal parts of about 4.69 ¢ each. Each step represents a frequency ratio of 21/256, or the 256th root of 2.

256edo is enfactored in the 5-limit with the same tuning as 128edo, and the error of harmonic 7 leads to inconsistency, which is likely one of the reasons this edo attracts little interest. To start with, consider the sharp-tending 256c val 256 406 595 719 886], which tempers out 2401/2400, 3388/3375, 5120/5103, so that it supports 7-limit hemififths and 11-limit semihemi. The patent val 256 406 594 719 886] tempers out 540/539, 2200/2187, 4000/3969, 12005/11979, among others. It is best tuned in the 2.3.7.11 subgroup, in which it is consistent to the 11-odd-limit minus intervals involving 5.

In the higher limits, it approximates harmonics 23, 43, and 47 quite accurately.

Odd harmonics

Approximation of odd harmonics in 256edo
Harmonic 3 5 7 9 11 13 15 17 19 21 23
Error Absolute (¢) +1.17 -1.94 +1.49 +2.34 +1.81 -1.47 -0.77 -1.83 -2.20 -2.03 -0.15
Relative (%) +25.0 -41.4 +31.7 +49.9 +38.6 -31.3 -16.4 -39.0 -46.9 -43.3 -3.2
Steps
(reduced)
406
(150)
594
(82)
719
(207)
812
(44)
886
(118)
947
(179)
1000
(232)
1046
(22)
1087
(63)
1124
(100)
1158
(134)

Subsets and supersets

Since 256 factors into 28, 256edo has subset edos 2, 4, 8, 16, 32, 64, and 128.