What are 7th 9th and 11th chords?
Similarly, what is the 11th of a chord?
In music theory, an eleventh chord is a chord that contains the tertian extension of the eleventh. Typically found in jazz, an eleventh chord also usually includes the seventh and ninth, and elements of the basic triad structure. Variants include the dominant eleventh, minor eleventh, and the major eleventh chord.
Similarly, how do you find the 9th of a chord?
In order to make a major 9 chord just stack another minor third on top of the B, or 7th, of the chord. A minor third away from B is D. D would be the major 9th of C. Just tag that note on to the C major 7th chord to get your C major 9 chord.
#11 chords are often used to spice up Tonic chords (I) and Sub-Dominant chords (IV). This is a very "off balance" sound, and comes up in jazz a good bit. A C#11 chord could be voiced as a D with a C bass, or D/C.