# 1200edo

← 1199edo | 1200edo | 1201edo → |

^{4}× 3 × 5^{2}**1200 equal divisions of the octave** (abbreviated **1200edo** or **1200ed2**), also called **1200-tone equal temperament** (**1200tet**) or **1200 equal temperament** (**1200et**) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 1200 equal parts of exactly 1 ¢ each. Each step represents a frequency ratio of 2^{1/1200}, or the 1200th root of 2.

1200edo is notable for being the equal division of the octave whose step size corresponds to exactly 1 cent.

## Theory

1200edo is distinctly consistent through the 11-odd-limit. This means that whole-cent approximations of the 11-odd-limit tonality diamond intervals are conveniently represented through the 11-limit patent val ⟨1200 1902 2786 3369 4151]. It is enfactored in the 5-limit, having the same tuning as 600edo.

The equal temperament tempers out 2460375/2458624 and 95703125/95551488 in the 7-limit, supporting the 171 & 1029 temperament, with a period of 1/3 octave and a generator which is an approximate 225/224 of 7\1200. It tempers out 9801/9800, 234375/234256 and 825000/823543 in the 11-limit, supporting the 494 & 706 temperament, with a half-octave period and an approximate 99/98 generator of 17\1200.

It also provides a 7-limit val, 1200ccd, which is extremely closely close to the 7-limit POTE tuning of quadritikleismic temperament: ⟨1200 1902 2785 3368]. It also provides the optimal patent val for the 224 & 976 temperament tempering out 2200/2197, 4096/4095, 9801/9800 and 35750/35721.

Upwards to the 47-limit, 1200edo offers relatively accurate approximations for 2, 3, 7, 17, 31, 41, and 47, and in the 2.3.7.17.31.41.47 subgroup it tempers out 2304/2303, 3808/3807, 6273/6272, 506447/506268, 632056/632043, 10218313/10214416. The 47th harmonic is 6666 steps and 666 steps reduced – a mathematical coincidence in our decimal system.

### Prime harmonics

Harmonic | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|

Error | Absolute (¢) | +0.000 | +0.045 | -0.314 | +0.174 | -0.318 | +0.472 | +0.045 | +0.487 | -0.274 | +0.423 | -0.036 |

Relative (%) | +0.0 | +4.5 | -31.4 | +17.4 | -31.8 | +47.2 | +4.5 | +48.7 | -27.4 | +42.3 | -3.6 | |

Steps (reduced) |
1200 (0) |
1902 (702) |
2786 (386) |
3369 (969) |
4151 (551) |
4441 (841) |
4905 (105) |
5098 (298) |
5428 (628) |
5830 (1030) |
5945 (1145) |

### Subsets and supersets

The nontrivial divisors of 1200 are 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 25, 30, 40, 48, 50, 60, 75, 80, 100, 120, 150, 200, 240, 300, 400, and 600. These are all the edos whose step size is an integer amount of cents, and thus can be played exactly on any digital audio workstation that offers detuning by cents.

## Regular temperament properties

Subgroup | Comma list | Mapping | Optimal 8ve Stretch (¢) |
Tuning Error | |
---|---|---|---|---|---|

Absolute (¢) | Relative (%) | ||||

2.3.5.7 | 2460375/2458624, 95703125/95551488, [36 -5 0 -10⟩ | [⟨1200 1902 2786 3369]] | +0.0112 | 0.0748 | 7.48 |

2.3.5.7.11 | 9801/9800, 234375/234256, 825000/823543, 1771561/1769472 | [⟨1200 1902 2786 3369 4151]] | +0.0273 | 0.0743 | 7.43 |

## Music

*Like scattered blue light*(2024)

*Dream Up*(2021, demo version)