20:25:30:36
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| Harmonics | 20:25:30:36 |
| Subharmonics | 1/(45:36:30:25) |
| Intervals from root | 1/1 – 5/4 – 3/2 – 9/5 |
| Cents from root | 0¢ 386¢ 702¢ 1018¢ |
| Step intervals | 5/4, 6/5, 6/5 |
| Step cents | 386¢, 316¢, 316¢ |
| Color name | yo gu-7 or y,g7 |
| Prime limit | 5 |
| Genus | 32 ⋅ 52 (225) |
| Intervallic odd limit | 25 |
| Otonal odd limit | 25 |
| Utonal odd limit | 45 |
20:25:30:36 is a major-minor seventh chord, sometimes considered a form of dominant seventh chord. It combines a 5/4 major third with the consonant 9/5 seventh that would be found in a minor seventh chord on the same root, creating a 36/25 tritone between the two.
The major-minor seventh chord is found rooted at the I (1⁄1) and IV (4⁄3) of the duodene.
In the meantone tuning of this chord, the ~9/5 seventh is equated with ~16/9, making it equivalent to the meantone tuning of 36:45:54:64.
In the septimal meantone tuning of this chord, the ~36/25 tritone is equated with the more consonant interval 10/7, and the major-minor seventh chord becomes an essentially tempered chord in the 9-odd-limit.