Hemimage temperaments

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This is a collection of rank-2 temperaments tempering out the hemimage comma, [5 -7 -1 3 = 10976/10935. These include commatic, chromat, degrees, subfourth, and bisupermajor, considered below, as well as the following discussed elsewhere:

Chromat

The chromat temperament has a period of 1/3 octave and tempers out the hemimage (10976/10935) and the triwellisma (235298/234375). It is also described as an amity extension with third-octave period.

Subgroup: 2.3.5.7

Comma list: 10976/10935, 235298/234375

Mapping[3 4 5 6], 0 5 13 16]]

Wedgie⟨⟨ 15 39 48 27 34 2 ]]

mapping generators: ~63/50, ~28/27

Optimal tuning (POTE): ~63/50 = 1\3, ~28/27 = 60.528

Optimal ET sequence39d, 60, 99, 258, 357, 456

Badness: 0.057499

11-limit

Subgroup: 2.3.5.7.11

Comma list: 441/440, 4375/4356, 10976/10935

Mapping: [3 4 5 6 6], 0 5 13 16 29]]

Optimal tuning (POTE): ~44/35 = 1\3, ~28/27 = 60.430

Optimal ET sequence60e, 99e, 159, 258, 417d

Badness: 0.050379

13-limit

Subgroup: 2.3.5.7.11.13

Comma list: 364/363, 441/440, 625/624, 10976/10935

Mapping: [3 4 5 6 6 4], 0 5 13 16 29 47]]

Optimal tuning (POTE): ~44/35 = 1\3, ~28/27 = 60.428

Optimal ET sequence99ef, 159, 258, 417d

Badness: 0.046006

17-limit

Subgroup: 2.3.5.7.11.13.17

Comma list: 364/363, 375/374, 441/440, 595/594, 3773/3757

Mapping: [3 4 5 6 6 4 10], 0 5 13 16 29 47 15]]

Optimal tuning (POTE): ~44/35 = 1\3, ~28/27 = 60.438

Optimal ET sequence99ef, 159, 258, 417dg

Badness: 0.031678

Catachrome

Subgroup: 2.3.5.7.11.13

Comma list: 325/324, 441/440, 1001/1000, 10976/10935

Mapping: [3 4 5 6 6 12], 0 5 13 16 29 -6]]

Optimal tuning (POTE): ~44/35 = 1\3, ~28/27 = 60.378

Optimal ET sequence60e, 99e, 159

Badness: 0.043844

17-limit

Subgroup: 2.3.5.7.11.13.17

Comma list: 273/272, 325/324, 375/374, 441/440, 4928/4913

Mapping: [3 4 5 6 6 12 10], 0 5 13 16 29 -6 15]]

Optimal tuning (POTE): ~44/35 = 1\3, ~28/27 = 60.377

Optimal ET sequence60e, 99e, 159

Badness: 0.030218

Chromic

Subgroup: 2.3.5.7.11.13

Comma list: 196/195, 352/351, 729/728, 1875/1859

Mapping: [3 4 5 6 6 9], 0 5 13 16 29 14]]

Optimal tuning (POTE): ~44/35 = 1\3, ~27/26 = 60.456

Optimal ET sequence60e, 99ef, 159f, 258ff

Badness: 0.049857

17-limit

Subgroup: 2.3.5.7.11.13.17

Comma list: 170/169, 196/195, 352/351, 375/374, 595/594

Mapping: [3 4 5 6 6 9 10], 0 5 13 16 29 14 15]]

Optimal tuning (POTE): ~63/50 = 1\3, ~27/26 = 60.459

Optimal ET sequence60e, 99ef, 159f, 258ff

Badness: 0.031043

Hemichromat

Subgroup: 2.3.5.7.11

Comma list: 3025/3024, 10976/10935, 102487/102400

Mapping: [3 4 5 6 10], 0 10 26 32 5]]

Optimal tuning (CTE): ~63/50 = 1\3, ~55/54 = 30.2511

Optimal ET sequence39d, 120cd, 159, 198, 357, 912b

Badness: 0.067173

13-limit

Subgroup: 2.3.5.7.11.13

Comma list: 676/675, 1001/1000, 3025/3024, 10976/10935

Mapping: [3 4 5 6 10 8], 0 10 26 32 5 41]]

Optimal tuning (CTE): ~63/50 = 1\3, ~55/54 = 30.2527

Optimal ET sequence39df, 120cdff, 159, 198, 357, 912b

Badness: 0.033420

Bisupermajor

Subgroup: 2.3.5.7

Comma list: 10976/10935, 65625/65536

Mapping[2 1 6 1], 0 8 -5 17]]

mapping generators: ~1225/864, ~192/175

Wedgie⟨⟨ 16 -10 34 -53 9 107 ]]

Optimal tuning (POTE): ~1225/864 = 1\2, ~192/175 = 162.806

Optimal ET sequence22, 74d, 96d, 118, 140, 258, 398, 656d

Badness: 0.065492

11-limit

Subgroup: 2.3.5.7.11

Comma list: 385/384, 3388/3375, 9801/9800

Mapping: [2 1 6 1 8], 0 8 -5 17 -4]]

Optimal tuning (POTE): ~99/70, ~11/10 = 162.773

Optimal ET sequence22, 74d, 96d, 118, 258e, 376de

Badness: 0.032080

Commatic

The commatic temperament has a period of half octave and a generator of 20.4 cents. It is so named because the generator is a small interval ("commatic") which represents 81/80, 99/98, and 100/99 all tempered together.

Subgroup: 2.3.5.7

Comma list: 10976/10935, 50421/50000

Mapping[2 3 4 5], 0 5 19 18]]

mapping generators: ~567/400, ~81/80

Wedgie⟨⟨ 10 38 36 37 29 -23 ]]

Optimal tuning (POTE): ~567/400 = 1\2, ~81/80 = 20.377

Optimal ET sequence58, 118, 294, 412d, 530d

Badness: 0.084317

11-limit

Subgroup: 2.3.5.7.11

Comma list: 441/440, 3388/3375, 8019/8000

Mapping: [2 3 4 5 6], 0 5 19 18 27]]

Optimal tuning (POTE): ~99/70 = 1\2, ~81/80 = 20.390

Optimal ET sequence58, 118, 294, 412d

Badness: 0.030461

13-limit

Subgroup: 2.3.5.7.11.13

Comma list: 196/195, 352/351, 729/728, 1001/1000

Mapping: [2 3 4 5 6 7], 0 5 19 18 27 12]]

Optimal tuning (POTE): ~99/70 = 1\2, ~66/65 = 20.427

Optimal ET sequence58, 118, 176f

Badness: 0.026336

17-limit

Subgroup: 2.3.5.7.11.13.17

Comma list: 170/169, 196/195, 289/288, 352/351, 561/560

Mapping: [2 3 4 5 6 7 8], 0 5 19 18 27 12 5]]

Optimal tuning (POTE): ~17/12 = 1\2, ~66/65 = 20.378

Optimal ET sequence58, 118, 294ffg, 412dffgg

Badness: 0.022396

Degrees

Degrees temperament has a period of 1/20 octave and tempers out the hemimage (10976/10935) and the dimcomp (390625/388962). In this temperament, one period equals ~28/27, two equals ~15/14, three equals ~10/9, five equals ~25/21, six equals ~16/13, seven equals ~14/11, nine equals ~15/11, and ten equals ~99/70.

An obvious extension to the 23-limit exists by equating 4\20 = 1\5 with 23/20, 6\20 = 3\10 with 69/56, 7\20 with 23/18, etc. By observing that 1\20 works as 30/29~29/28~28/27, with 29/28 being especially accurate, and by equating 29/22 with 2\5 = 240 ¢, we get a uniquely elegant extension to the 29-limit which tempers out (33/25)/(29/22) = 726/725, S28 = 784/783 and S29 = 841/840. An edo as large as 220 supports it by patent val, though it does not appear in the optimal ET sequence, and 80edo and 140edo are both much more recommendable tunings.

By equating 37/28 with 2\5 and more accurately 85/74 with 1\5 and 44/37 with 1\4 (among many other equivalences) we get an extension to prime 37 agreeing with many (semi)convergents. By equating 60/41~41/28 with 11\20 or equivalently 56/41~41/30 with 9\20 and by equating 44/41 with 1\10 (among many other equivalences) there is a very efficient extension to prime 41.

By looking at the mapping, we observe an 80-note mos scale is ideal, so that 80edo is in some sense both a trivial and maximally efficient tuning of this temperament. We also observe an abundance of JI interpretations of 20edo by combining primes so that all things require 3 generators, yielding: 37:44:54:56:58:60:69:74:82:85. Alternatively, combining primes so that all things require 2 generators yields 36:40:46:51 which except for intervals of 51 is contained implicitly in the above. The ratios therein should thus be instructive for how the structure of 20edo relates to its representation of JI in this temperament. Note that prime 47 can be added but only really makes sense in rooted form in 140edo.

Subgroup: 2.3.5.7

Comma list: 10976/10935, 390625/388962

Mapping[20 0 -17 -39], 0 1 2 3]]

mapping generators: ~28/27, ~3

Wedgie⟨⟨ 20 40 60 17 39 27 ]]

Optimal tuning (POTE): ~28/27 = 1\20, ~3/2 = 703.015 (~126/125 = 16.985)

Optimal ET sequence20cd, 60, 80, 140, 640b, 780b

Badness: 0.106471

Badness (Dirichlet): 2.694

11-limit

Subgroup: 2.3.5.7.11

Comma list: 1331/1323, 1375/1372, 2200/2187

Mapping: [20 0 -17 -39 -26], 0 1 2 3 3]]

Optimal tuning (POTE): ~28/27 = 1\20, ~3/2 = 703.231 (~100/99 = 16.769)

Optimal ET sequence20cd, 60e, 80, 140, 360

Badness: 0.046770

Badness (Dirichlet): 1.546

13-limit

Subgroup: 2.3.5.7.11.13

Comma list: 325/324, 352/351, 1001/1000, 1331/1323

Mapping: [20 0 -17 -39 -26 74], 0 1 2 3 3 0]]

Optimal tuning (POTE): ~28/27 = 1\20, ~3/2 = 703.080 (~100/99 = 16.920)

Optimal ET sequence20cde, 60e, 80, 140

Badness: 0.032718

Badness (Dirichlet): 1.352

17-limit

Subgroup: 2.3.5.7.11.13.17

Comma list: 289/288, 325/324, 352/351, 561/560, 1001/1000

Mapping: [20 0 -17 -39 -26 74 50], 0 1 2 3 3 0 1]]

Optimal tuning (CTE): ~28/27 = 1\20, ~3/2 = 703.107 (~100/99 = 16.893)

Optimal ET sequence20cde, 60e, 80, 140

Badness (Dirichlet): 1.171

19-limit

Subgroup: 2.3.5.7.11.13.17.19

Comma list: 286/285, 289/288, 325/324, 352/351, 400/399, 476/475

Mapping: [20 0 -17 -39 -26 74 50 85], 0 1 2 3 3 0 1 0]]

Optimal tuning (CTE): ~28/27 = 1\20, ~3/2 = 703.107 (~100/99 = 16.893)

Optimal ET sequence20cde, 60e, 80, 140

Badness (Dirichlet): 1.273

23-limit

Subgroup: 2.3.5.7.11.13.17.19.23

Comma list: 253/252, 286/285, 289/288, 325/324, 352/351, 391/390, 400/399

Mapping: [20 0 -17 -39 -26 74 50 85 27], 0 1 2 3 3 0 1 0 2]]

Optimal tuning (CTE): ~28/27 = 1\20, ~3/2 = 703.169 (~100/99 = 16.831)

Optimal ET sequence20cdei, 60e, 80, 140

Badness (Dirichlet): 1.209

29-limit

Subgroup: 2.3.5.7.11.13.17.19.23.29

Comma list: 253/252, 286/285, 289/288, 325/324, 352/351, 391/390, 400/399, 406/405

Mapping: [20 0 -17 -39 -26 74 50 85 27 2], 0 1 2 3 3 0 1 0 2 3]]

Optimal tuning (CTE): ~29/28 = 1\20, ~3/2 = 703.171 (~100/99 = 16.829)

Optimal ET sequence20cdeij, 60e, 80, 140

Badness (Dirichlet): 1.134

no-31's 37-limit

Subgroup: 2.3.5.7.11.13.17.19.23.29.37

Comma list: 253/252, 286/285, 289/288, 325/324, 352/351, 391/390, 400/399, 406/405, 481/480

Mapping: [20 0 -17 -39 -26 74 50 85 27 2 9], 0 1 2 3 3 0 1 0 2 3 3]]

Optimal tuning (CTE): ~29/28 = 1\20, ~3/2 = 703.222 (~100/99 = 16.778)

Optimal ET sequence20cdeijl, 60el, 80, 140

Badness (Dirichlet): 1.127

no-31's 41-limit

Subgroup: 2.3.5.7.11.13.17.19.23.29.37.41

Comma list: 253/252, 286/285, 289/288, 325/324, 352/351, 391/390, 400/399, 451/450, 476/475, 481/480, 2871/2870

Mapping: [20 0 -17 -39 -26 74 50 85 27 2 9 12], 0 1 2 3 3 0 1 0 2 3 3 3]]

Optimal tuning (CTE): ~29/28 = 1\20, ~3/2 = 703.207

Optimal ET sequence20cdeijlm, 60el, 80, 140

Badness (Dirichlet): 1.100

Squarschmidt

A generator for the squarschimidt temperament is the fourth root of 5/2, (5/2)1/4, tuned around 396.6 cents. The squarschimidt temperament can be described as 118&239 temperament, tempering out the hemimage comma and quasiorwellisma, 29360128/29296875 in the 7-limit. In the 11-limit, 118&239 tempers out 3025/3024, 5632/5625, and 12005/11979, and the generator represents ~44/35.

Subgroup: 2.3.5

Comma list: [61 4 -29

Mapping[1 -8 1], 0 29 4]]

mapping generators: ~2, ~98304/78125

Optimal tuning (POTE): ~2 = 1\1, ~98304/78125 = 396.621

Optimal ET sequence118, 593, 711, 829, 947

Badness: 0.218314

7-limit

Subgroup: 2.3.5.7

Comma list: 10976/10935, 29360128/29296875

Mapping[1 -8 1 -20], 0 29 4 69]]

Wedgie⟨⟨ 29 4 69 -61 28 149 ]]

Optimal tuning (POTE): ~2 = 1\1, ~1125/896 = 396.643

Optimal ET sequence118, 239, 357, 596, 1549bd

Badness: 0.132821

11-limit

Subgroup: 2.3.5.7.11

Comma list: 3025/3024, 5632/5625, 10976/10935

Mapping: [1 -8 1 -20 -21], 0 29 4 69 74]]

Optimal tuning (POTE): ~2 = 1\1, ~44/35 = 396.644

Optimal ET sequence118, 239, 357, 596

Badness: 0.038186

Subfourth

Subgroup: 2.3.5.7

Comma list: 10976/10935, 65536/64827

Mapping[1 0 17 4], 0 4 -37 -3]]

mapping generators: ~2, ~21/16

Wedgie⟨⟨ 4 -37 -3 -68 -16 97 ]]

Optimal tuning (POTE): ~2 = 1\1, ~21/16 = 475.991

Optimal ET sequence58, 121, 179, 300bd, 479bcd

Badness: 0.140722

11-limit

Subgroup: 2.3.5.7.11

Comma list: 540/539, 896/891, 12005/11979

Mapping: [1 0 17 4 11], 0 4 -37 -3 -19]]

Optimal tuning (POTE): ~2 = 1\1, ~21/16 = 475.995

Optimal ET sequence58, 121, 179e, 300bde

Badness: 0.045323

13-limit

Subgroup: 2.3.5.7.11.13

Comma list: 352/351, 364/363, 540/539, 676/675

Mapping: [1 0 17 4 11 16], 0 4 -37 -3 -19 -31]]

Optimal tuning (POTE): ~2 = 1\1, ~21/16 = 475.996

Optimal ET sequence58, 121, 179ef, 300bdef

Badness: 0.023800