Seventeen limit tetrads
The 17th harmonic, octave reduced to the frequency ratio 17/16, is about 105¢. It is likely to sound dissonant against the fundamental, which is perhaps one reason why Just Intonation composers usually stop at the 13-limit or lower. Another interval of 17 that can sound just as dissonant is 18/17, about 99¢. Thus, 17/16 also clashes with 9/8. Therefore, one approach for 17-limit harmony is to filter the total list of chords to exclude these small steps, resulting in non-rooted harmonies.
Every otonal tetrad within the 17-limit is listed in the table below as the simplest possible subset of harmonics 2-17; there are 56 in total. The columns to the right of the chords provide different cutoffs for filtering out small steps. For example, chords with a 16/15 cutoff do not contain any interval smaller than or equal to 16/15 (which includes 17/16 and 18/17) among the dyads. Since this eliminates harmonics 2 and 9 right away, it also eliminates chords containing 10/9 and 9/8. (This is why there is a jump from 12/11 to 9/8 in the table below.)
no cutoff
56 tetrads |
16/15 cutoff
20 tetrads |
15/14 cutoff
16 tetrads |
14/13 cutoff
13 tetrads |
13/12 cutoff
10 tetrads |
12/11 cutoff
7 tetrads |
9/8 cutoff
4 tetrads |
17/15 cutoff
1 tetrad |
---|---|---|---|---|---|---|---|
2:3:5:17 | |||||||
2:3:7:17 | |||||||
2:3:9:17 | |||||||
2:3:11:17 | |||||||
2:3:13:17 | |||||||
2:3:15:17 | |||||||
2:5:7:17 | |||||||
2:5:9:17 | |||||||
2:5:11:17 | |||||||
2:5:13:17 | |||||||
2:5:15:17 | |||||||
2:7:9:17 | |||||||
2:7:11:17 | |||||||
2:7:13:17 | |||||||
2:7:15:17 | |||||||
2:9:11:17 | |||||||
2:9:13:17 | |||||||
2:9:15:17 | |||||||
2:11:13:17 | |||||||
2:11:15:17 | |||||||
2:13:15:17 | |||||||
3:5:7:17 | x | x | x | x | x | x | x |
3:5:9:17 | |||||||
3:5:11:17 | x | x | x | x | |||
3:5:13:17 | x | x | x | ||||
3:5:15:17 | x | x | x | x | x | x | |
3:7:9:17 | |||||||
3:7:11:17 | x | x | x | x | |||
3:7:13:17 | x | x | |||||
3:7:15:17 | x | ||||||
3:9:11:17 | |||||||
3:9:13:17 | |||||||
3:9:15:17 | |||||||
3:11:13:17 | x | x | x | ||||
3:11:15:17 | x | x | x | x | |||
3:13:15:17 | x | x | x | ||||
5:7:9:17 | |||||||
5:7:11:17 | x | x | x | x | x | ||
5:7:13:17 | x | x | |||||
5:7:15:17 | x | ||||||
5:9:11:17 | |||||||
5:9:13:17 | |||||||
5:9:15:17 | |||||||
5:11:13:17 | x | x | x | x | x | ||
5:11:15:17 | x | x | x | x | x | ||
5:13:15:17 | x | x | x | x | x | x | |
7:9:11:17 | |||||||
7:9:13:17 | |||||||
7:9:15:17 | |||||||
7:11:13:17 | x | x | |||||
7:11:15:17 | x | ||||||
7:13:15:17 | x | ||||||
9:11:13:17 | |||||||
9:11:15:17 | |||||||
9:13:15:17 | |||||||
11:13:15:17 | x | x | x | x | x | x | |