Father–3 equivalence continuum/Godtone's approach

From Xenharmonic Wiki
Revision as of 23:35, 26 February 2025 by Godtone (talk | contribs) (the father-3 continuum is so bad that i didnt realise it was supposed to be equivalent to this continuum until now. i propose replacing it with this continuum and reworking the temperaments from there into here, but if that isnt acceptable i still believe this continuum should be documented and named as such)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

The augmented-chromatic equivalence continuum is a continuum of 5-limit temperaments which equates a number of 128/125's (augmented commas) with the chroma, 25/24. As such, it represents the continuum of all 5-limit temperaments supported by 3edo.

This formulation has a specific reason: 128/125 is significantly smaller than 25/24, so that it makes sense to equate some number of 128/125's with 25/24, but because 25/24 = (25/16)/(3/2), this has the consequence of clearly relating the n in (128/125)n = 25/24 with how many 5/4's are used to reach 3/2 (when octave-reduced):

If n = 0, then it takes no 128/125's to reach 25/24, implying 25/24's size is 0 (so that it's tempered out), meaning that 3/2 is reached via (5/4)2.

For integer n > 0, we always reach 25/24 via (25/16)/(128/125)n because of (128/125)n ~ 25/24 by definition, meaning that we reach 3/2 at 3n + 2 generators of ~5/4, octave-reduced.

The just value of n is log2(25/24) / log2(128/125) = 1.72125... where n = 2 corresponds to Würschmidt's comma.

Temperaments with integer n
n Temperament Comma
Ratio Monzo
0 Dicot (7 & 10) 25/24 [-3 -1 2
1 Magic (19 & 22) 3125/3072 [-10 -1 5
2 Würschmidt (31 & 34) 393216/390625 [17 1 -8
3 Magus (43 & 46) 50331648/48828125 [24 1 -11
4 Supermagus (55 & 58) 6442450944/6103515625 [31 1 -14
5 Ultramagus (67 & 70) 824633720832/762939453125 [38 1 -17
Augmented (12 & 15) 128/125 [-7 0 3
Temperaments with half-integer n
n Temperament Comma
Ratio Monzo
1/2 Wesley (26 & 29) 78125/73728 [13 2 -7
3/2 Ditonic (50 & 53) 1220703125/1207959552 [-27 -2 13
5/2 Novamajor (77 & 80) 19791209299968/19073486328125 [41 2 -19
7/2 3 & 101 (36 digits) [55 2 -25