4:5:6:7:9

Revision as of 05:10, 26 November 2025 by Overthink (talk | contribs) (+ notes on extensions and see also section)

4:5:6:7:9, the harmonic ninth chord, is a pentad in 7-limit harmony. It serves as the fundamental otonal consonance of the 9-odd-limit, with many chords being a subset of it or one of its inversions. Its utonal inverse, 1/(4:5:6:7:9), can also be seen as a fundamental chord, and subsets can be taken out of it as well. The 4:5:6:7:9 chord can be modified to get its utonal inverse by inflecting both the third and seventh up by 36/35, so the third becomes 9/7 and the seventh 9/5. It is an extension of 4:5:6 and 4:5:6:7.

Chord information
Harmonics 4:5:6:7:9
Subharmonics 1/(315:252:210:180:140)
Intervals from root 1/15/43/27/49/4
Cents from root 386¢702¢969¢1404¢
Step intervals 5/4, 6/5, 7/6, 9/7
Step cents 386¢, 316¢, 267¢, 435¢
Color names yo zo-7 add-9 or y,z7,9
har-9 or h9
Prime limit 7
Genus 3257 (315)
Intervallic odd limit 9
Otonal odd limit 9
Utonal odd limit 315
Consistent edos (d ≥ 1.5) 31edo, 41edo*, 46edo, 53edo, …

See also