EDO

An equal division of the octave (EDO or edo, /ˈidoʊ/ EE-doh) is a tuning system constructed by dividing the octave into a number of equal steps.

The dominant modern tuning system may be called 12edo (12-EDO) because it divides the octave into 12 semitones that are all the same size. It may also be called 12-tone equal temperament or 12-TET, but this is discouraged because it does not specify which interval is being equally divided.

List of Edos

Very incomplete edo table. Popular edos are highlighted.

Edo	Description	First twelve steps, from 0¢	Possible erac subgroup
5	The basic equipentatonic, and the smallest edo to have strong melodic properties. Good approximation of 2.3.7 for its size.	240, 480, 720, 960, 1200	2.>>3.<7
6	Subset of 12edo. Good approximation of 2.9.5.7 for its size, such as in Didacus temperament.	200, 400, 600, 800, 1000, 1200	2.>5.>>7
7	The basic equiheptatonic, and the first edo to (very vaguely) support diatonic functional harmony.	171.4, 342.9, 514.3, 685.7, 857.1, 1028.6, 1200
9	The first edo to support the antidiatonic scale and temperaments like semabila, loosely resembling the pelog scale. It contains approximations to many 7-limit intervals, but not the 7/4 itself.	133.3, 266.7, 400, 533.3, 666.7, 800, 933.3, 1066.7, 1200	2.<<3.>5.<<7
10	The doubling of 5edo, useful as an interval categorization archetype and as a melodic system in its own right, supporting mosh.	120, 240, 360, 480, 600, 720, 840, 960, 1080, 1200	2.>>3.<7.13
12	The basic tuning of diatonic, and consequently the most widespread EDO. Supports the 5-limit decently well.	100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200	2.3.>5.>>7
...	...	...	...
15	The basic tuning of Zarlino's intense diatonic, a subset of Blackwood which is itself a degenerate tuning of blackdye. Supporting porcupine temperament and dubitably the 11-limit.	80, 160, 240, 320, 400, 480, 560, 640, 720, 800, 880, 960
...	...	...	...
22	Represents the 7-limit and 11-limit decently well, serving as the primary tuning of pajara and also a decent archy tuning.	54.5, 109.1, 163.6, 218.2, 272.7, 327.3, 381.8, 436.4, 490.9, 545.5, 600, 654.5	2.3.5.>7.11
...	...	...	...
31	The definitive Septimal Meantone tuning.	38.7, 77.4, 116.1, 154.8, 193.5, 232.3, 271.0, 309.7, 348.4, 387.1, 425.8, 464.5	2.3.5.7