There is a difference between a major ninth chord and a dominant ninth chord. A dominant ninth is the combination of a dominant chord (with a minor seventh) and a major ninth. A major ninth chord (e.g., Cmaj9), as an extended chord, adds the major seventh along with the ninth to the major triad. Thus, a Cmaj9 consists of C E G B and D . When the symbol "9" is not preceded by the word "major" or "maj" (e.g., C9), the chord is a dominant ninth. That is, the implied seventh chord is a dominant seventh, i.e. a major triad plus the minor seventh, to which the ninth is added: e.g., a C9 consists of C, E, G, B and D . C dominant ninth (C9) would usually be expected to resolve to an F major chord (the implied key, C being the dominant of F). The ninth is commonly chromatically altered by half-step either up or down to create more tension and dissonance. Fétis tuned the chord 4:5:6:7:9.