September chords
September chords are essentially tempered dyadic chords tempered by the september comma, 715/714.
There are 20 triads, 76 tetrads, 60 pentads, and 10 hexads as 17-odd-limit essentially tempered chords.
For triads, there are 10 pairs of chords in inverse relationship:
| Inversely related pairs of triads | |
|---|---|
| 1 – 14/11 – 5/3 (steps 14/11, 17/13, 6/5) |
1 – 6/5 – 11/7 (steps 6/5, 17/13, 14/11) |
| 1 – 12/11 – 10/7 (steps 12/11, 17/13, 7/5) |
1 – 7/5 – 11/6 (steps 7/5, 17/13, 12/11) |
| 1 – 14/13 – 5/3 (steps 14/13, 17/11, 6/5) |
1 – 6/5 – 13/7 (steps 6/5, 17/11, 14/13) |
| 1 – 13/12 – 7/5 (steps 13/12, 22/17, 10/7) |
1 – 10/7 – 24/13 (steps 10/7, 22/17, 13/12) |
| 1 – 13/12 – 14/11 (steps 13/12, 20/17, 11/7) |
1 – 11/7 – 24/13 (steps 11/7, 20/17, 13/12) |
| 1 – 12/11 – 13/7 (steps 12/11, 17/10, 14/13) |
1 – 14/13 – 11/6 (steps 14/13, 17/10, 12/11) |
| 1 – 11/9 – 17/13 (steps 11/9, 15/14, 26/17) |
1 – 15/14 – 17/13 (steps 15/14, 11/9, 26/17) |
| 1 – 13/9 – 17/11 (steps 13/9, 15/14, 22/17) |
1 – 15/14 – 17/11 (steps 15/14, 13/9, 22/17) |
| 1 – 14/11 – 13/9 (steps 14/11, 17/15, 18/13) |
1 – 18/13 – 11/7 (steps 18/13, 17/15, 14/11) |
| 1 – 18/11 – 13/7 (steps 18/11, 17/15, 14/13) |
1 – 14/13 – 11/9 (steps 14/13, 17/15, 18/11) |
For tetrads, there are 38 pairs of chords in inverse relationship:
| Inversely related pairs of tetrads | |
|---|---|
| 1 – 13/12 – 7/5 – 3/2 (steps 13/12, 22/17, 15/14, 4/3) |
1 – 15/14 – 18/13 – 3/2 (steps 15/14, 22/17, 13/12, 4/3) |
| 1 – 7/5 – 3/2 – 11/6 (steps 7/5, 15/14, 11/9, 12/11) |
1 – 15/14 – 3/2 – 18/11 (steps 15/14, 7/5, 12/11, 11/9) |
| 1 – 18/13 – 3/2 – 30/17 (steps 18/13, 13/12, 20/17, 17/15) |
1 – 13/12 – 3/2 – 17/10 (steps 13/12, 18/13, 17/15, 20/17) |
| 1 – 17/15 – 11/9 – 4/3 (steps 17/15, 14/13, 12/11, 3/2) |
1 – 12/11 – 20/17 – 4/3 (steps 12/11, 14/13, 17/15, 3/2) |
| 1 – 14/11 – 14/9 – 5/3 (steps 14/11, 11/9, 15/14, 6/5) |
1 – 6/5 – 9/7 – 11/7 (steps 6/5, 15/14, 11/9, 14/11) |
| 1 – 14/11 – 17/11 – 5/3 (steps 14/11, 17/14, 14/13, 6/5) |
1 – 6/5 – 22/17 – 11/7 (steps 6/5, 14/13, 17/14, 14/11) |
| 1 – 14/11 – 13/9 – 5/3 (steps 14/11, 17/15, 15/13, 6/5) |
1 – 6/5 – 18/13 – 11/7 (steps 6/5, 15/13, 17/15, 14/11) |
| 1 – 14/11 – 15/11 – 5/3 (steps 14/11, 15/14, 11/9, 6/5) |
1 – 6/5 – 22/15 – 11/7 (steps 6/5, 11/9, 15/14, 14/11) |
| 1 – 9/7 – 18/13 – 11/7 (steps 9/7, 14/13, 17/15, 14/11) |
1 – 14/11 – 13/9 – 14/9 (steps 14/11, 17/15, 14/13, 9/7) |
| 1 – 14/11 – 13/9 – 17/11 (steps 14/11, 17/15, 15/14, 22/17) |
1 – 22/17 – 18/13 – 11/7 (steps 22/17, 15/14, 17/15, 14/11) |
| 1 – 17/14 – 10/7 – 17/11 (steps 17/14, 20/17, 13/12, 22/17) |
1 – 17/14 – 11/7 – 17/10 (steps 17/14, 22/17, 13/12, 20/17) |
| 1 – 13/11 – 13/9 – 17/11 (steps 13/11, 11/9, 15/14, 22/17) |
1 – 15/14 – 17/13 – 17/11 (steps 15/14, 11/9, 13/11, 22/17) |
| 1 – 17/15 – 13/9 – 17/11 (steps 17/15, 14/11, 15/14, 22/17) |
1 – 17/15 – 22/15 – 11/7 (steps 17/15, 22/17, 15/14, 14/11) |
| 1 – 17/13 – 17/12 – 11/6 (steps 17/13, 13/12, 22/17, 12/11) |
1 – 13/12 – 17/12 – 17/11 (steps 13/12, 17/13, 12/11, 22/17) |
| 1 – 17/13 – 17/11 – 5/3 (steps 17/13, 13/11, 14/13, 6/5) |
1 – 6/5 – 22/17 – 26/17 (steps 6/5, 14/13, 13/11, 17/13) |
| 1 – 17/13 – 20/13 – 5/3 (steps 17/13, 20/17, 13/12, 6/5) |
1 – 6/5 – 13/10 – 26/17 (steps 6/5, 13/12, 20/17, 17/13) |
| 1 – 17/13 – 10/7 – 5/3 (steps 17/13, 12/11, 7/6, 6/5) |
1 – 6/5 – 7/5 – 26/17 (steps 6/5, 7/6, 12/11, 17/13) |
| 1 – 17/13 – 17/12 – 5/3 (steps 17/13, 13/12, 20/17, 6/5) |
1 – 6/5 – 24/17 – 26/17 (steps 6/5, 20/17, 13/12, 17/13) |
| 1 – 17/13 – 5/3 – 17/9 (steps 17/13, 14/11, 17/15, 18/17) |
1 – 17/13 – 18/13 – 11/7 (steps 17/13, 18/17, 17/15, 14/11) |
| 1 – 17/13 – 5/3 – 11/6 (steps 17/13, 14/11, 11/10, 12/11) |
1 – 17/13 – 10/7 – 11/7 (steps 17/13, 12/11, 11/10, 14/11) |
| 1 – 17/13 – 17/10 – 11/6 (steps 17/13, 13/10, 14/13, 12/11) |
1 – 14/13 – 7/5 – 11/6 (steps 14/13, 13/10, 17/13, 12/11) |
| 1 – 17/13 – 22/13 – 11/6 (steps 17/13, 22/17, 13/12, 12/11) |
1 – 13/12 – 7/5 – 11/6 (steps 13/12, 22/17, 17/13, 12/11) |
| 1 – 15/11 – 17/11 – 5/3 (steps 15/11, 17/15, 14/13, 6/5) |
1 – 6/5 – 22/17 – 22/15 (steps 6/5, 14/13, 17/15, 15/11) |
| 1 – 13/11 – 14/11 – 13/9 (steps 13/11, 14/13, 17/15, 18/13) |
1 – 17/15 – 11/9 – 13/9 (steps 17/15, 14/13, 13/11, 18/13) |
| 1 – 7/5 – 17/10 – 11/6 (steps 7/5, 17/14, 14/13, 12/11) |
1 – 17/14 – 17/10 – 13/7 (steps 17/14, 7/5, 12/11, 14/13) |
| 1 – 17/12 – 17/10 – 11/6 (steps 17/12, 6/5, 14/13, 12/11) |
1 – 6/5 – 17/10 – 13/7 (steps 6/5, 17/12, 12/11, 14/13) |
| 1 – 6/5 – 22/17 – 7/5 (steps 6/5, 14/13, 13/12, 10/7) |
1 – 13/12 – 7/6 – 7/5 (steps 13/12, 14/13, 6/5, 10/7) |
| 1 – 11/10 – 22/17 – 7/5 (steps 11/10, 20/17, 13/12, 10/7) |
1 – 13/12 – 14/11 – 7/5 (steps 13/12, 20/17, 11/10, 10/7) |
| 1 – 13/12 – 13/10 – 7/5 (steps 13/12, 6/5, 14/13, 10/7) |
1 – 14/13 – 22/17 – 7/5 (steps 14/13, 6/5, 13/12, 10/7) |
| 1 – 13/9 – 17/11 – 17/9 (steps 13/9, 15/14, 11/9, 18/17) |
1 – 11/9 – 17/13 – 17/9 (steps 11/9, 15/14, 13/9, 18/17) |
| 1 – 13/9 – 17/11 – 13/7 (steps 13/9, 15/14, 6/5, 14/13) |
1 – 15/14 – 17/11 – 5/3 (steps 15/14, 13/9, 14/13, 6/5) |
| 1 – 13/9 – 17/11 – 5/3 (steps 13/9, 15/14, 14/13, 6/5) |
1 – 14/13 – 15/13 – 5/3 (steps 14/13, 15/14, 13/9, 6/5) |
| 1 – 17/15 – 11/9 – 17/13 (steps 17/15, 14/13, 15/14, 26/17) |
1 – 15/14 – 15/13 – 17/13 (steps 15/14, 14/13, 17/15, 26/17) |
| 1 – 14/13 – 11/9 – 17/13 (steps 14/13, 17/15, 15/,14 26/17) |
1 – 15/14 – 17/14 – 17/13 (steps 15/14, 17/15, 14/13, 26/17) |
| 1 – 17/11 – 5/3 – 17/9 (steps 17/11, 14/13, 17/15, 18/17) |
1 – 17/15 – 11/9 – 17/9 (steps 17/15, 14/13, 17/11, 18/17) |
| 1 – 17/11 – 17/10 – 13/7 (steps 17/11, 11/10, 12/11, 14/13) |
1 – 12/11 – 6/5 – 13/7 (steps 12/11, 11/10, 17/11, 14/13) |
| 1 – 11/7 – 17/10 – 13/7 (steps 11/7, 13/12, 12/11, 14/13) |
1 – 13/12 – 17/10 – 11/6 (steps 13/12, 11/7, 14/13, 12/11) |
| 1 – 11/7 – 17/10 – 11/6 (steps 11/7, 13/12, 14/13, 12/11) |
1 – 13/12 – 17/10 – 13/7 (steps 13/12, 11/7, 12/11, 14/13) |
For pentads, there are 30 pairs of chords in inverse relationship:
| Inversely related pairs of pentads | |
|---|---|
| 1 – 13/12 – 13/10 – 7/5 – 3/2 (steps 13/12, 6/5, 14/13, 15/14, 4/3) |
1 – 15/14 – 15/13 – 18/13 – 3/2 (steps 15/14, 14/13, 6/5, 13/12, 4/3) |
| 1 – 13/12 – 7/6 – 7/5 – 3/2 (steps 13/12, 14/13, 6/5, 15/14, 4/3) |
1 – 15/14 – 9/7 – 18/13 – 3/2 (steps 15/14, 6/5, 14/13, 13/12, 4/3) |
| 1 – 7/6 – 7/5 – 3/2 – 11/6 (steps 7/6, 6/5, 15/14, 11/9, 12/11) |
1 – 15/14 – 9/7 – 3/2 – 18/11 (steps 15/14, 6/5, 7/6, 12/11, 11/9) |
| 1 – 15/13 – 18/13 – 3/2 – 30/17 (steps 15/13, 6/5, 13/12, 20/17, 17/15) |
1 – 13/12 – 13/10 – 3/2 – 17/10 (steps 13/12, 6/5, 15/13, 17/15, 20/17) |
| 1 – 11/10 – 7/5 – 3/2 – 11/6 (steps 11/10, 14/11, 15/14, 11/9, 12/11) |
1 – 15/14 – 15/11 – 3/2 – 18/11 (steps 15/14, 14/11, 11/10, 12/11, 11/9) |
| 1 – 13/12 – 17/12 – 3/2 – 17/10 (steps 13/12, 17/13, 18/17, 17/15, 20/17) |
1 – 18/17 – 18/13 – 3/2 – 30/17 (steps 18/17, 17/13, 13/12, 20/17, 17/15) |
| 1 – 13/12 – 7/5 – 3/2 – 11/6 (steps 13/12, 22/17, 15/14, 11/9, 12/11) |
1 – 15/14 – 18/13 – 3/2 – 18/11 (steps 15/14, 22/17, 13/12, 12/11, 11/9) |
| 1 – 13/12 – 7/5 – 3/2 – 17/10 (steps 13/12, 22/17, 15/14, 17/15, 20/17) |
1 – 15/14 – 18/13 – 3/2 – 30/17 (steps 15/14, 22/17, 13/12, 20/17, 17/15) |
| 1 – 17/12 – 3/2 – 17/10 – 11/6 (steps 17/12, 18/17, 17/15, 14/13, 12/11) |
1 – 18/17 – 3/2 – 18/11 – 30/17 (steps 18/17, 17/12, 12/11, 14/13, 17/15) |
| 1 – 7/5 – 3/2 – 17/10 – 11/6 (steps 7/5, 15/14, 17/15, 14/13, 12/11) |
1 – 15/14 – 3/2 – 18/11 – 30/17 (steps 15/14, 7/5, 12/11, 14/13, 17/15) |
| 1 – 18/13 – 3/2 – 18/11 – 30/17 (steps 18/13, 13/12, 12/11, 14/13, 17/15) |
1 – 13/12 – 3/2 – 17/10 – 11/6 (steps 13/12, 18/13, 17/15, 14/13, 12/11) |
| 1 – 15/11 – 3/2 – 18/11 – 30/17 (steps 15/11, 11/10, 12/11, 14/13, 17/15) |
1 – 11/10 – 3/2 – 17/10 – 11/6 (steps 11/10, 15/11, 17/15, 14/13, 12/11) |
| 1 – 13/12 – 14/11 – 17/11 – 5/3 (steps 13/12, 20/17, 17/14, 14/13, 6/5) |
1 – 14/13 – 17/13 – 20/13 – 5/3 (steps 14/13, 17/14, 20/17, 13/12, 6/5) |
| 1 – 14/13 – 14/11 – 14/9 – 5/3 (steps 14/13, 13/11, 11/9, 15/14, 6/5) |
1 – 15/14 – 17/13 – 17/11 – 5/3 (steps 15/14, 11/9, 13/11, 14/13, 6/5) |
| 1 – 17/14 – 17/13 – 10/7 – 11/7 (steps 17/14, 14/13, 12/11, 11/10, 14/11) |
1 – 11/10 – 6/5 – 22/17 – 11/7 (steps 11/10, 12/11, 14/13, 17/14, 14/11) |
| 1 – 6/5 – 22/17 – 22/15 – 11/7 (steps 6/5, 14/13, 17/15, 15/14, 14/11) |
1 – 15/14 – 17/14 – 17/13 – 11/7 (steps 15/14, 17/15, 14/13, 6/5, 14/11) |
| 1 – 6/5 – 22/17 – 18/13 – 11/7 (steps 6/5, 14/13, 15/14, 17/15, 14/11) |
1 – 17/15 – 17/14 – 17/13 – 11/7 (steps 17/15, 15/14, 14/13, 6/5, 14/11) |
| 1 – 6/5 – 9/7 – 18/13 – 11/7 (steps 6/5, 15/14, 14/13, 17/15, 14/11) |
1 – 17/15 – 11/9 – 17/13 – 11/7 (steps 17/15, 14/13, 15/14, 6/5, 14/11) |
| 1 – 17/15 – 11/9 – 22/15 – 11/7 (steps 17/15, 14/13, 6/5, 15/14, 14/11) |
1 – 15/14 – 9/7 – 18/13 – 11/7 (steps 15/14, 6/5, 14/13, 17/15, 14/11) |
| 1 – 17/15 – 6/5 – 22/15 – 11/7 (steps 17/15, 18/17, 11/9, 15/14, 14/11) |
1 – 15/14 – 17/13 – 18/13 – 11/7 (steps 15/14, 11/9, 18/17, 17/15, 14/11) |
| 1 – 17/14 – 17/13 – 10/7 – 17/11 (steps 17/14, 14/13, 12/11, 13/12, 22/17) |
1 – 13/12 – 13/11 – 14/11 – 17/11 (steps 13/12, 12/11, 14/13, 17/14, 22/17) |
| 1 – 13/11 – 14/11 – 13/9 – 17/11 (steps 13/11, 14/13, 17/15, 15/14, 22/17) |
1 – 15/14 – 17/14 – 17/13 – 17/11 (steps 15/14, 17/15, 14/13, 13/11, 22/17) |
| 1 – 17/13 – 17/11 – 5/3 – 17/9 (steps 17/13, 13/11, 14/13, 17/15, 18/17) |
1 – 13/11 – 17/11 – 18/11 – 13/7 (steps 13/11, 17/13, 18/17, 17/15, 14/13) |
| 1 – 17/13 – 17/12 – 5/3 – 11/6 (steps 17/13, 13/12, 20/17, 11/10, 12/11) |
1 – 13/12 – 17/12 – 17/11 – 17/10 (steps 13/12, 17/13, 12/11, 11/10, 20/17) |
| 1 – 17/13 – 10/7 – 17/11 – 5/3 (steps 17/13, 12/11, 13/12, 14/13, 6/5) |
1 – 14/13 – 7/6 – 14/11 – 5/3 (steps 14/13, 13/12, 12/11, 17/13, 6/5) |
| 1 – 17/13 – 10/7 – 20/13 – 5/3 (steps 17/13, 12/11, 14/13, 13/12, 6/5) |
1 – 13/12 – 7/6 – 14/11 – 5/3 (steps 13/12, 14/13, 12/11, 17/13, 6/5) |
| 1 – 17/13 – 17/12 – 17/11 – 5/3 (steps 17/13, 13/12, 12/11, 14/13, 6/5) |
1 – 14/13 – 20/17 – 14/11 – 5/3 (steps 14/13, 12/11, 13/12, 17/13, 6/5) |
| 1 – 13/12 – 17/12 – 17/11 – 5/3 (steps 13/12, 17/13, 12/11, 14/13, 6/5) |
1 – 14/13 – 20/17 – 20/13 – 5/3 (steps 14/13, 12/11, 17/13, 13/12, 6/5) |
| 1 – 13/9 – 17/11 – 5/3 – 17/9 (steps 13/9, 15/14, 14/13, 17/15, 18/17) |
1 – 17/15 – 11/9 – 17/13 – 17/9 (steps 17/15, 14/13, 15/14, 13/9, 18/17) |
| 1 – 11/10 – 6/5 – 22/17 – 7/5 (steps 11/10, 12/11, 14/13, 13/12, 10/7) |
1 – 13/12 – 7/6 – 14/11 – 7/5 (steps 13/12, 14/13, 12/11, 11/10, 10/7) |
For hexads, there are 5 pairs of chords in inverse relationship:
| Inversely related pairs of hexads | |
|---|---|
| 1 – 13/12 – 13/10 – 7/5 – 3/2 – 17/10 (steps 13/12, 6/5, 14/13, 15/14, 17/15, 20/17) |
1 – 15/14 – 15/13 – 18/13 – 3/2 – 30/17 (steps 15/14, 14/13, 6/5, 13/12, 20/17, 17/15) |
| 1 – 13/12 – 7/6 – 7/5 – 3/2 – 11/6 (steps 13/12, 14/13, 6/5, 15/14, 11/9, 12/11) |
1 – 15/14 – 9/7 – 18/13 – 3/2 – 18/11 (steps 15/14, 6/5, 14/13, 13/12, 12/11, 11/9) |
| 1 – 11/10 – 7/5 – 3/2 – 17/10 – 11/6 (steps 11/10, 14/11, 15/14, 17/15, 14/13, 12/11) |
1 – 15/14 – 15/11 – 3/2 – 18/11 – 30/17 (steps 15/14, 14/11, 11/10, 12/11, 14/13, 17/15) |
| 1 – 13/12 – 17/12 – 3/2 – 17/10 – 11/6 (steps 13/12, 17/13, 18/17, 17/15, 14/13, 12/11) |
1 – 18/17 – 18/13 – 3/2 – 18/11 – 30/17 (steps 18/17, 17/13, 13/12, 12/11, 14/13, 17/15) |
| 1 – 13/12 – 7/5 – 3/2 – 17/10 – 11/6 (steps 13/12, 22/17, 15/14, 17/15, 14/13, 12/11) |
1 – 15/14 – 18/13 – 3/2 – 18/11 – 30/17 (steps 15/14, 22/17, 13/12, 12/11, 14/13, 17/15) |
Equal temperaments with september chords include 31, 41, 46, 72, 87, 94, 103, 111, 121, 140, 183, 224 and 270.