117edo
← 116edo | 117edo | 118edo → |
117 equal divisions of the octave (abbreviated 117edo or 117ed2), also called 117-tone equal temperament (117tet) or 117 equal temperament (117et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 117 equal parts of about 10.3 ¢ each. Each step represents a frequency ratio of 21/117, or the 117th root of 2.
117edo is inconsistent to the 5-odd-limit and higher odd limits, with four mappings possible for the 11-limit: ⟨117 185 272 328 405] (patent val), ⟨117 186 272 329 405] (117bd), ⟨117 185 271 328 404] (117ce), and ⟨117 185 272 329 405] (117d).
Using the patent val, it tempers out 81/80 (syntonic comma) and [69 -1 -29⟩ in the 5-limit; 6144/6125, 31104/30625, and 403368/390625 in the 7-limit, supporting the 7-limit mohajira temperament; 540/539, 1344/1331, 1617/1600, and 3168/3125 in the 11-limit, supporting the rank-3 terpsichore temperament; 144/143, 196/195, 364/363, 729/715, and 3146/3125 in the 13-limit.
Using the 117d val, it tempers out 126/125, 225/224, and [29 3 0 -12⟩ in the 7-limit; 99/98, 176/175, 441/440, and 12582912/12400927 in the 11-limit; 144/143, 640/637, 648/637, 1001/1000, and 43940/43923 in the 13-limit, supporting the 13-limit grosstone temperament.
Using the 117ce val, it tempers out 3125/3072 (magic comma) and [-31 24 -3⟩ in the 5-limit; 2401/2400, 3645/3584, and 4375/4374 in the 7-limit; 243/242, 441/440, and 1815/1792 in the 11-limit; 105/104, 275/273, 1287/1280, and 2025/2002 in the 13-limit.
Using the 117bd val, it tempers out 15625/15552 (kleisma) and [34 -17 -3⟩ in the 5-limit; 245/243, 3136/3125, and 51200/50421 in the 7-limit; 176/175, 1232/1215, 1375/1372, and 2560/2541 in the 11-limit; 169/168, 364/363, 640/637, 832/825, and 3200/3159 in the 13-limit.
Odd harmonics
Harmonic | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | -4.52 | +3.43 | -4.72 | +1.22 | +2.53 | +0.50 | -1.09 | -2.39 | -0.08 | +1.01 | -2.63 |
Relative (%) | -44.1 | +33.4 | -46.1 | +11.9 | +24.7 | +4.9 | -10.6 | -23.3 | -0.8 | +9.9 | -25.7 | |
Steps (reduced) |
185 (68) |
272 (38) |
328 (94) |
371 (20) |
405 (54) |
433 (82) |
457 (106) |
478 (10) |
497 (29) |
514 (46) |
529 (61) |
Subsets and supersets
Since 117 factors into 32 × 13, 117edo has subset edos 3, 9, 13, and 39. 234edo, which doubles it, provides a correction for the approximation to harmonic 3.