Würschmidt

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Würschmidt
Subgroups 2.3.5, 2.3.5.23
Comma basis 393216/390625 (2.3.5);
576/575, 12167/12150 (2.3.5.23)
Reduced mapping <1; 8 1 14]
Edo join 31 & 34
Generator (CTE) ~5/4 = 387.734c
MOS scales 3L 1s, 3L 4s ... 3L 28s, 31L 3s
Ploidacot beta-octacot
Minmax error (5-odd limit) 1.43c;
((2.3.5.23) 25-odd limit) 2.86c
Target scale size (5-odd limit) 19 notes;
((2.3.5.23) 25-odd limit) 34 notes

Würschmidt is a rank-2 temperament and parent of the würschmidt family, characterized by tempering out the würschmidt comma, 393216/390625. It can be treated as analogous to schismatic with the roles of the primes 3 and 5 reversed, since würschmidt is generated by a classical major third (5/4), very slightly sharpened so that eight of them make the sixth harmonic (6/1), giving 3/2 the same complexity 5/4 does in schismatic, but with comparable accuracy on the part of the generator. Four generators, therefore, reach the interval 625/512, which is equated to 768/625 and functions as a neutral third.

For technical data, see Würschmidt family #Würschmidt.

Extensions

Another useful interpretation of the würschmidt comma is that it makes the interval of 25/24 equal to two-thirds the size of 16/15. This can be exploited, as 16/15 factorizes into near-2:1 parts as (24/23) × (46/45), and therefore it is illogical not to set 25/24 equal to 24/23 (and 128/125 equal to 46/45) as well and set the remainder, 46/45, equal to a third of 16/15, by tempering S24 = 576/575 and S462 × S47 = 12167/12150 in the 2.3.5.23 subgroup. A perhaps more direct way of seeing why equating 25/24 with 24/23 is natural is that würschmidt's generator is a slightly sharpened 5/4 with a slightly flat 3/2 in an optimised tuning, so that 25/24 is sharpened and 24/n is flattened, so equating it with 24/23 takes advantage of the natural tempering tendency. 14 generators turn out to stack to 23/1, and notably, 6/1 stacked 7 times and 23/1 stacked four times (at 56 generators) differ only by the 0.59-cent comma 279936/279841 = S49 / (S1612).

Strong extensions to the 7-limit include septimal würschmidt (tempering out 225/224, finding 7 at +18 generator steps), worschmidt (tempering out 126/125, finding 7 at -13 generator steps), and whirrschmidt (tempering out 4375/4374, finding 7 at +52 generator steps), but these are either considerably higher-damage or much higher-complexity than 5-limit würschmidt. In fact, the best septimal extension may be the weak extension hemiwürschmidt, which splits the ~5/4 generator into two ~28/25's by tempering out 3136/3125 alongside 6144/6125 (notably, in the 2.3.5.7.23 subgroup, this is the extension that tempers out the tiny comma S161 = 25921/25920).

Therefore, it may be advisable to consider würschmidt a no-sevens system, specifically in the 2.3.5.11 subgroup, where an extension that equates 128/125 with 45/44 and therefore 625/512 with 11/9 (by tempering out 243/242 and 5632/5625), finding the 11th harmonic at 20 generators up, is highly natural in addition to the aforementioned extension to prime 23.

Interval chain

In the below, octave-reduced harmonics 1–125 are indicated in bold. All intervals are in the 625-odd limit.

# Cents* Approximate ratios
2.3.5.23 subgroup Add-11 extension
0 0.00 1/1
1 387.652 5/4, 144/115 69/55
2 775.304 25/16, 36/23 69/44, 352/225
3 1162.956 45/23, 125/64, 736/375 88/45, 108/55
4 350.608 92/75, 225/184, 625/512 11/9, 27/22
5 738.260 23/15, 192/125 55/36, 135/88
6 1125.912 23/12, 48/25 44/23
7 313.564 6/5, 115/96 55/46
8 701.216 3/2 121/81
9 1088.868 15/8, 216/115 207/110, 253/135
10 276.520 27/23, 75/64 88/75, 207/176
11 664.172 184/125, 135/92, 375/256 22/15, 81/55
12 1051.824 46/25, 675/368 11/6, 81/44
13 239.476 23/20, 144/125 55/48, 132/115
14 627.128 23/16, 36/25 33/23
15 1014.780 9/5, 115/64 165/92, 242/135
16 202.432 9/8 121/108
17 590.084 45/32, 162/115 253/180
18 977.736 81/46, 225/128 44/25
19 165.388 138/125, 405/368 11/10, 243/220
20 553.040 69/50, 864/625 11/8, 243/176
21 940.692 69/40, 216/125 55/32
22 128.344 27/25, 69/64 99/92
23 515.996 27/20, 345/256
24 903.648 27/16 253/150
25 91.300 135/128, 243/230 132/125, 253/240
26 478.952 243/184, 828/625 33/25, 253/192
27 866.604 207/125 33/20
28 54.256 207/200, 648/625 33/32
29 441.908 162/125, 207/160 165/128
30 829.560 81/50, 207/128 121/75
31 17.212 81/80 121/120

* In 5-limit CTE tuning

Tunings

Optimized tunings

Prime-optimized tunings
Weight-skew\Order Euclidean
Constrained Destretched
Tenney (2.3.5) CTE: ~5/4 = 387.734¢ (2.3.5) POTE: ~5/4 = 387.7993¢
Weil (2.3.5) CWE: ~5/4 = 387.776¢
Equilateral (2.3.5) CEE: ~5/4 = 387.7224¢

(8/65-comma)

Tenney (2.3.5.23) CTE: ~5/4 = 387.734¢ (2.3.5.23) POTE: ~5/4 = 387.8051¢
Weil (2.3.5.23) CWE: ~5/4 = 387.781¢
DR and equal-beating tunings
Optimized chord Generator value Polynomial Further notes
3:4:5 (+1 +1) ~5/4 = 387.4975 g8 + 8g − 16 = 0 1–3–5 equal-beating tuning, close to 3/29-comma
4:5:6 (+1 +1) ~5/4 = 388.1207 g8 − 8g + 8 = 0 1–3–5 equal-beating tuning, close to 3/19-comma
10:12:15 (+2 +3) ~5/4 = 388.2216 g8 − 2g7 + 4 = 0 Close to 1/6-comma
15:18:23 (+3 +5) ~5/4 = 387.9215 4g7 − 3g5 − 10 = 0

Tuning spectrum

The below assumes the 2.3.5.11.23 subgroup extension. Note that "e" and "i" are the warts for primes 11 and 23, respectively.

Edo
generator
Eigenmonzo
(unchanged-interval)
*
Generator (¢) Comments
9\28 385.7143 28ei val
5/4 386.3137 Untempered tuning, lower bound of 5-odd-limit diamond tradeoff
10\31 387.0968 Lower bound of 2.3.5.23-subgroup 25-odd-limit diamond monotone
23/22 387.1739
375/256 387.3542 1/11-comma
41\127 387.4016 127e val
11/6 387.4469
75/64 387.4582 1/10-comma
31\96 387.5000
11/8 387.5659
52\161 387.5776
15/8 387.5854 1/9-comma
73\226 387.6106
11/10 387.6318
45/32 387.6602 2/17-comma
21\65 387.6923
23/12 387.7199
23/16 387.7338
116\359 387.7437 359ee val
3/2 387.7444 1/8-comma
95\294 387.7551 294e val
74\229 387.7729 229e val
53\164 387.8049 164e val
23/18 387.8178 1/2 S24
85\263 387.8327 263ee val
9/5 387.8393 2/15-comma
23/20 387.8431
32\99 387.8788 99e val
75\232 387.9310 232eei val
5/3 387.9490 1/7-comma, upper bound of 5-odd-limit diamond tradeoff
43\133 387.9699 133e val
25/23 387.9706
23/15 388.0011
54\167 388.0240 167eei val
25/24 388.2213 1/6-comma, upper bound of 2.3.5.23-subgroup 25-odd-limit diamond tradeoff
11\34 388.2353
125/96 388.6028 1/5-comma
23\71 388.7324 71eei val
625/384 389.1750 1/4-comma
12\37 389.1892 37eei val
1\3 400.0000 Upper bound of 2.3.5.23-subgroup 25-odd-limit diamond monotone

* Besides the octave

Other tunings

  • DKW (2.3.5): ~2 = 1\1, ~5/4 = 387.8015
  • 5-odd-limit minimax: ~2 = 1\1, ~5/4 = 387.7444 (eigenmonzo 3/2 aka 1/8-comma, generator = 61/8)

Music

Chris Vaisvil
  • Ancient Stardust (2013) – blog | play – Würschmidt[13] in 5-odd-limit minimax tuning
Jake Freivald
  • Extrospection (2013) – play | SoundCloud – Würschmidt[16] in 31edo tuning.