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{{Infobox ET}}
{{Infobox ET}}
The '''777 equal divisions of the octave''', or the 777-tone equal temperament (777tet), 777 equal temperament (777et) when viewed from a regular temperament perspective, divides the octave into 777 equal parts of about 1.544 cents each.
{{EDO intro|777}}


== Theory ==
777edo is a [[dual-fifth system]] with a [[consistency|consistency limit]] of only 3, but otherwise it is excellent in approximating harmonics [[5/1|5]], [[7/1|7]], [[9/1|9]], [[11/1|11]], and [[13/1|13]], making it suitable for a 2.9.5.7.11.13 [[subgroup]] interpretation with the comma basis {4459/4455, 41503/41472, 496125/495616, 123201/123200, 105644/105625}. In addition, it tempers out the [[landscape comma]] in the 2.9.5.7 subgroup.
 
777edo is a dual fifths system with a consistency limit of only 3.
 
If the harmonic 3 is excluded, it is an excellent 2.5.7.9.11.13 subgroup tuning, with the comma basis {4459/4455, 41503/41472, 496125/495616, 123201/123200, 105644/105625}. In addition, it tempers out the [[landscape comma]] in the 2.9.5.7 subgroup.


=== Odd harmonics ===
{{Harmonics in equal|777}}
{{Harmonics in equal|777}}


[[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->
=== Subsets and supersets ===
Since 777 factors into 3 × 7 × 37, 777edo has subset edos {{EDOs| 3, 7, 21, 37, 111, and 333 }}.

Revision as of 11:52, 20 October 2023

← 776edo 777edo 778edo →
Prime factorization 3 × 7 × 37
Step size 1.5444 ¢ 
Fifth 455\777 (702.703 ¢) (→ 65\111)
Semitones (A1:m2) 77:56 (118.9 ¢ : 86.49 ¢)
Dual sharp fifth 455\777 (702.703 ¢) (→ 65\111)
Dual flat fifth 454\777 (701.158 ¢)
Dual major 2nd 132\777 (203.861 ¢) (→ 44\259)
Consistency limit 3
Distinct consistency limit 3

Template:EDO intro

777edo is a dual-fifth system with a consistency limit of only 3, but otherwise it is excellent in approximating harmonics 5, 7, 9, 11, and 13, making it suitable for a 2.9.5.7.11.13 subgroup interpretation with the comma basis {4459/4455, 41503/41472, 496125/495616, 123201/123200, 105644/105625}. In addition, it tempers out the landscape comma in the 2.9.5.7 subgroup.

Odd harmonics

Approximation of odd harmonics in 777edo
Harmonic 3 5 7 9 11 13 15 17 19 21 23
Error Absolute (¢) +0.748 -0.213 -0.486 -0.049 +0.033 -0.373 +0.534 +0.064 +0.556 +0.262 +0.297
Relative (%) +48.4 -13.8 -31.5 -3.2 +2.2 -24.2 +34.6 +4.1 +36.0 +16.9 +19.2
Steps
(reduced)
1232
(455)
1804
(250)
2181
(627)
2463
(132)
2688
(357)
2875
(544)
3036
(705)
3176
(68)
3301
(193)
3413
(305)
3515
(407)

Subsets and supersets

Since 777 factors into 3 × 7 × 37, 777edo has subset edos 3, 7, 21, 37, 111, and 333.