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An example of 25/24 chroma

🔗Gene Ward Smith <gwsmith@svpal.org>

3/22/2003 7:30:13 PM

If we were to be completely systematic, the place to have begun this
investigation would have been the 5-limit and 25/24 as a chroma; as
Paul pointed out, the locus classicus for all of this is 81/80 as a
comma, 25/24 as a chroma, leading to 81/80[7], better known as the
diatonic scale. There are other possibilities, some known and some
completely unknown. I give an example in the latter category.

Name?[89]
This may have been given one, but I couldn't find it

Comma
381520424476945831628649898809/381469726562500000000000000000

Scale
[1, 31381059609/31250000000, 1594323/1562500,
7812500000000/7625597484987, 250/243, 129140163/125000000, 6561/6250,
205891132094649/195312500000000, 62500/59049, 27/25,
847288609443/781250000000, 15625000/14348907,
312500000000/282429536481, 10/9, 3486784401/3125000000,
3906250000/3486784401, 78125000000000/68630377364883, 2500/2187,
14348907/12500000, 729/625, 22876792454961/19531250000000,
625000/531441, 59049/50000, 6/5, 94143178827/78125000000,
156250000/129140163, 3125000000000/2541865828329, 100/81,
387420489/312500000, 39062500000/31381059609,
617673396283947/488281250000000, 25000/19683, 1594323/1250000,
2541865828329/1953125000000, 6250000/4782969, 6561/5000, 4/3,
10460353203/7812500000, 1562500000/1162261467, 27/20, 1000/729,
43046721/31250000, 390625000000/282429536481,
68630377364883/48828125000000, 250000/177147, 177147/125000,
97656250000000/68630377364883, 282429536481/195312500000,
62500000/43046721, 729/500, 40/27, 1162261467/781250000,
15625000000/10460353203, 3/2, 10000/6561, 4782969/3125000,
3906250000000/2541865828329, 2500000/1594323, 19683/12500,
617673396283947/390625000000000, 31381059609/19531250000,
625000000/387420489, 81/50, 2541865828329/1562500000000,
129140163/78125000, 156250000000/94143178827, 5/3, 100000/59049,
531441/312500, 39062500000000/22876792454961, 1250/729,
25000000/14348907, 2187/1250, 68630377364883/39062500000000,
3486784401/1953125000, 6250000000/3486784401, 9/5,
282429536481/156250000000, 14348907/7812500,
1562500000000/847288609443, 50/27, 59049/31250,
390625000000000/205891132094649, 12500/6561, 250000000/129140163,
243/125, 7625597484987/3906250000000, 3125000/1594323,
62500000000/31381059609]

Generator order
[3906250000/3486784401, 27/20, 2541865828329/1562500000000,
3125000/1594323, 59049/50000, 97656250000000/68630377364883, 1250/729,
129140163/125000000, 39062500000/31381059609, 3/2,
282429536481/156250000000, 15625000/14348907, 6561/5000,
617673396283947/390625000000000, 12500/6561, 14348907/12500000,
390625000000/282429536481, 5/3, 31381059609/31250000000,
156250000/129140163, 729/500, 68630377364883/39062500000000,
62500/59049, 1594323/1250000, 3906250000000/2541865828329, 50/27,
3486784401/3125000000, 1562500000/1162261467, 81/50,
7625597484987/3906250000000, 625000/531441, 177147/125000,
39062500000000/22876792454961, 250/243, 387420489/312500000,
15625000000/10460353203, 9/5, 847288609443/781250000000,
6250000/4782969, 19683/12500, 390625000000000/205891132094649,
2500/2187, 43046721/31250000, 156250000000/94143178827, 1,
94143178827/78125000000, 62500000/43046721, 2187/1250,
205891132094649/195312500000000, 25000/19683, 4782969/3125000,
1562500000000/847288609443, 10/9, 10460353203/7812500000,
625000000/387420489, 243/125, 22876792454961/19531250000000,
250000/177147, 531441/312500, 7812500000000/7625597484987, 100/81,
1162261467/781250000, 6250000000/3486784401, 27/25,
2541865828329/1953125000000, 2500000/1594323, 59049/31250,
78125000000000/68630377364883, 1000/729, 129140163/78125000,
62500000000/31381059609, 6/5, 282429536481/195312500000,
25000000/14348907, 6561/6250, 617673396283947/488281250000000,
10000/6561, 14348907/7812500, 312500000000/282429536481, 4/3,
31381059609/19531250000, 250000000/129140163, 729/625,
68630377364883/48828125000000, 100000/59049, 1594323/1562500,
3125000000000/2541865828329, 40/27, 3486784401/1953125000]

Generator = 94143178827/78125000000

Generator circle of triads
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 36/25]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 6/5, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]
[1, 5/4, 3/2]