There is a difference between a major ninth chord and a dominant ninth chord. A dominant ninth is the combination of a dominant chord and a major ninth. A major ninth chord, 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" , 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 would usually be expected to resolve to an F major chord. 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. In the common practice period, "the root, 3rd, 7th, and 9th are the most common factors present in the V9 chord," with the 5th, "typically omitted". The ninth and seventh usually resolve downward to the fifth and third of I. Example of tonic dominant ninth chords include Bobby Gentry's and Wild Cherry's "Play That Funky Music". James Brown's features a striking dominant 9th arpeggio played staccato at the end of the opening 12-bar sequence. The opening phrase of Chopin's well-known "Minute Waltz" climaxes on a dominant 9th chord: César Franck’s Violin Sonata in A Major opens with a dominant ninth chord in the piano part. When the violin enters in the fifth bar, its melody articulates an arpeggio of this chord. Debussy’s "Hommage a Rameau", the second of his first Book of Images for piano solo climaxes powerfully on a dominant 9th, expressed both as a chord and as a wide-ranging arpeggio: The starting point of Karlheinz Stockhausen’s piece for vocal sextet, is a chord consisting of the notes B, F, B, D, A and C. According to Cook, Stimmung could, in terms of conventional tonal harmony, be viewed as ‘simply a dominant ninth chord that is subject to timbral variation. The notes the performers sing are harmonics 2, 3, 4, 5, 7, and 9 of the implied but absent fundamental—the B flat below the bass clef.’
Dominant minor ninth
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A dominant minor ninth chord consists of a dominant seventh chord and a minor ninth. In C: C E G B D. Fétis tuned the chord 8:10:12:14:17. In notation for jazz and popular music, this chord is often denoted, e.g., C79. In Franz Schubert’s Song Der Erlkönig'', a terrified child calls out to his father when he sees an apparition of the sinister Elf King. The dissonant voicing of the dominant minor ninth chord used here is particularly effective in heightening the drama and sense of threat. << \new ChordNames \chordmode
Writing about this passage, Taruskin remarks on the “unprecedented… level of dissonance at the boy’s outcries…The voice has the ninth, pitched above, and the left hand has the seventh, pitched below. The result is a virtual ‘tone cluster’…the harmonic logic of these progressions, within the rules of composition Schubert was taught, can certainly be demonstrated. That logic, however, is not what appeals so strongly to the listener’s imagination; rather it is the calculated impression of wild abandon.”
Minor ninth
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The minor ninth chord consist of a minor seventh chord and a major ninth. The formula is 1, 3, 5, 7, 9. This chord is written as Cm9. This chord has a more "bluesy" sound and fits very well with the dominant ninth.
Major ninth
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Notable examples
In una stanza con poca luce
The major ninth chord consists of a major seventh chord and a major ninth. The formula is 1, 3, 5, 7, 9. This chord is written as Cmaj9.
6/9 chord
The 6/9 chord is a pentad with a major triad extended by a sixth and ninth above the root, but no seventh, thus: C6/9 is C,E,G,A,D. It is not a tense chord requiring resolution, and is considered a substitute for the tonic in jazz. The minor 6/9 chord is a minor triad with an added 6th of the Dorian mode and an added 9th, and is also suitable as a minor tonic in jazz. Heinrich Schenker, though he allowed the substitution of the dominant seventh, leading-tone, and leading tone half-diminished seventh chords, rejected the concept of a ninth chord on the basis that only that on the fifth scale degree was admitted and that inversion was not allowed of the ninth chord.
Second
In music, the secondfactor of a chord is the note or pitch two scale degrees above the root or tonal center. When the second is the bass note, or lowest note, of the expressed chord, the chord is in third inversion. However, this is equivalent to a gapped eleventh chord. Conventionally, the second is third in importance to the root, fifth, and third, being an added tone. It is generally not allowed as the bass note since that inversion resembles an eleventh chord on the second rather than an added tone chord on the original note. In jazz chords and jazz theory, the second is required due to its being an added tone. The quality of the second may be determined by the scale, or may be indicated. For example, in both a major and minor scale a diatonic second added to the tonic chord is major while one added to the dominant chord is major or minor, respectively. The second is octave equivalent to the ninth. If one could cut out the note in between the fifth and the ninth and then drop the ninth down an octave to a second, one would have a second chord. The difference between sus2 and add9 is conventionally the absence or presence, respectively, of the third.
Added ninth
An added ninth chord is a major triad with an added ninth. Thus, Cadd9 consists of C, E, G and D. Added ninth chords differ from other ninth chords because the seventh is never included.
