20:25:30:36

Chord information

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
Consistent edos (d≥2)	19edo**, 34edo*, 38edo*, 46edo*, …
* 2≤d<4; ** 4≤d<8; *** 8≤d<16; …

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.

If 128/125 is tempered out, this chord is tuned identically to both 256:320:375:450 and 128:160:192:225.