128edo: Difference between revisions

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Subsets and supersets: remove the statement since that is already said in the intro
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=== Subsets and supersets ===
=== Subsets and supersets ===
Since 128 factors into 2<sup>7</sup>, 128edo has subset edos {{EDOs| 2, 4, 8, 16, 32, and 64 }}.  
Since 128 factors into 2<sup>7</sup>, 128edo has subset edos {{EDOs| 2, 4, 8, 16, 32, and 64 }}.  
=== Miscellaneous properties ===
Being the power of two closest to division of the octave by the Germanic [[Wikipedia: long hundred|long hundred]], 128edo has a unit step which is the binary (fine) relative cent (or relative heptamu in MIDI terms) of [[1edo]].


== Regular temperament properties ==
== Regular temperament properties ==

Revision as of 14:02, 30 June 2023

← 127edo 128edo 129edo →
Prime factorization 27
Step size 9.375 ¢ 
Fifth 75\128 (703.125 ¢)
Semitones (A1:m2) 13:9 (121.9 ¢ : 84.38 ¢)
Consistency limit 7
Distinct consistency limit 7

Template:EDO intro It is notable for being the equal division corresponding to a standard MIDI piano roll of 128 notes.

Theory

128edo tempers out 2109375/2097152 in the 5-limit; 245/243, 1029/1024 and 5120/5103 in the 7-limit; 385/384 and 441/440 in the 11-limit. It provides the optimal patent val for 7-limit rodan, the 41 & 87 temperament, as well as for 7-limit fourfives, the 60 & 68 temperament.

See also 128 notes per octave on Alto Saxophone (Demo by Philipp Gerschlauer)

Prime harmonics

Approximation of prime harmonics in 128edo
Harmonic 2 3 5 7 11 13 17 19 23 29 31
Error Absolute (¢) +0.00 +1.17 -1.94 -3.20 +1.81 +3.22 -1.83 +2.49 -0.15 +1.67 -1.29
Relative (%) +0.0 +12.5 -20.7 -34.1 +19.3 +34.4 -19.5 +26.5 -1.6 +17.8 -13.7
Steps
(reduced)
128
(0)
203
(75)
297
(41)
359
(103)
443
(59)
474
(90)
523
(11)
544
(32)
579
(67)
622
(110)
634
(122)

Subsets and supersets

Since 128 factors into 27, 128edo has subset edos 2, 4, 8, 16, 32, and 64.

Regular temperament properties

Rank-2 temperaments by generators
Periods
per 8ve
Generator
(Reduced)
Cents
(Reduced)
Associated
Ratio
Temperaments
1 25\128 234.375 8/7 Rodan
1 29\128 271.875 75/64 Orson
1 33\128 309.375 448/375 Triwell
1 53\128 496.875 4/3 Undecental
2 13\128 121.875 15/14 Lagaca
2 15\128 140.625 27/25 Fifive
4 15\128 140.625 27/25 Fourfives
4 53\128
(11\128)
496.875
(103.125)
4/3 Undim (7-limit)

Scales