The major 3rd from harmonics 4 and 5. Play F horn, A horn, D-flat horn.
Try out a number of small intervals (smaller than a semitone) - microtones.
Relation to root Ratios Cents Second root
13 of 5 65:64 27
16 of 1 1:1 0 20 of -5
19 of -5 19:10 1111
15 of 1 15:8 1088 12 of 5
18 of -5 9:5 1018
14 of 1 7:4 969
11 of 5 55:32 938
17 of -5 17:10 919
13 of 1 13:8 841
16 of -5 8:5 814
10 of 5 25:16 773
12 of 1 3:2 702 15 of -5
9 of 5 45:32 590
14 of -5 7:5 583
11 of 1 11:8 551
13 of -5 13:10 454
10 of 1 5:4 386 8 of 5
12 of -5 6:5 316
9 of 1 9:8 204
11 of -5 11:10 165
7 of 5 35:32 155
8 of 1 8:1 0 10 of -5
6 of 5 15:8 1088
9 of -5 9:5 1018
7 of 1 7:4 969
8 of -5 8:5 814
5 of 5 25:16 773
6 of 1 3:2 702
7 of -5 7:5 583
5 of 1 5:4 386 4 of 5
6 of -5 6:5 316
5 of -5 4:1 0 4 of 1
3 of 5 15:8 1088
4 of -5 8:5 814
3 of 1 3:2 702
2 of 5 5:4 386
3 of -5 6:5 316
2 of 1 2:1 0
2 of -5 8:5 814
1 of 5 5:4 386
1 of 1 1:1 0
1 of -5 8:5 814