# 2118edo

← 2117edo | 2118edo | 2119edo → |

**2118 equal divisions of the octave** (abbreviated **2118edo** or **2118ed2**), also called **2118-tone equal temperament** (**2118tet**) or **2118 equal temperament** (**2118et**) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 2118 equal parts of about 0.567 ¢ each. Each step represents a frequency ratio of 2^{1/2118}, or the 2118th root of 2.

## Theory

Primes approximated with less than 1 standard deviation in 2118edo are: 2, 3, 5, 7, 11, 19, 23, 29, 31, 43. Overall, it offers excellent double-13's 31-limit harmony, as both mappings of 13 (2118 and 2118f vals) have useful interpretations.

2118edo provides a 43-limit approximation of secor with 46/43 (206 steps), however this reduces to 103\1059, meaning that it is a compound of two circles of such secor. In addition, it offers a 205-step generator "meantone secor" which is described by a 31 & 2118 temperament, also in the 2.3.5.7.11.23.43 subgroup, and also offers a meantone fifth. The comma basis for the "meantone secor" temperament is 5376/5375, 9317/9315, 25921/25920, 151263/151250, and 10551296/10546875.

### Prime harmonics

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

Error | Absolute (¢) | +0.000 | +0.028 | +0.089 | +0.013 | -0.043 | +0.266 | -0.140 | -0.063 | +0.054 | -0.115 | +0.007 |

Relative (%) | +0.0 | +4.9 | +15.6 | +2.2 | -7.6 | +46.9 | -24.6 | -11.0 | +9.6 | -20.4 | +1.2 | |

Steps (reduced) |
2118 (0) |
3357 (1239) |
4918 (682) |
5946 (1710) |
7327 (973) |
7838 (1484) |
8657 (185) |
8997 (525) |
9581 (1109) |
10289 (1817) |
10493 (2021) |

### Subsets and supersets

2118edo is 6 times the 353edo, meaning it can be used to play a compound of 6 chains of the rectified hebrew temperament.

## Regular temperament properties

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

Absolute (¢) | Relative (%) | ||||

2.3.5 | [38 -2 15⟩, [-11 130 -84⟩ | [⟨2118 3357 4918]] | -0.0186 | 0.0156 | |

2.3.5.7 | 250047/250000, [-1 -18 -3 13⟩, [38 -2 -15⟩ | [⟨2118 3357 4918 5946]] | -0.0150 | 0.0148 | |

2.3.5.7.11 | 9801/9800, 250047/250000, [25 1 -4 0 -5⟩, [16 -7 -9 2 3⟩ | [⟨2118 3357 4918 5946 7927]] | -0.0096 | 0.0172 |