Extended chords are chords that have extended or added notes beyond the seventh. These extended notes are all the other notes that form a chord, besides the “chord notes”. Remember that the chord notes are those which form the triad and tetrad of a chord. Let’s take as example Cmaj7 chord. It is formed by C, E, G and B notes, which correspond to first degrees 1, 3, 5 and 7. This is the tetrad of this chord, in other words, the notes C, E, G and B are called “chord notes” of Cmaj7.
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