The term sixth chord refers to two different kinds of chord, one in classical music and the other in modern popular music.
The original meaning of the term is a chord in first inversion, in other words with its third in the bass and its root a sixth above it. This is how the term is still used in classical music today, and in this sense it is called also a chord of the sixth.
In music or music theory, a thirteenth is the note thirteen scale degrees from the root of a chord and also the interval between the root and the thirteenth. The thirteenth is most commonly major or minor .
A thirteenth chord is the stacking of six (major or minor) thirds, the last being above the 11th of an eleventh chord. Thus a thirteenth chord is a tertian (built from thirds) chord containing the interval of a thirteenth, and is an extended chord if it includes the ninth and/or the eleventh. "The jazzy thirteenth is a very versatile chord and is used in many genres." Since 13th chords tend to become unclear or confused with other chords when inverted, they are generally found in root position. For example, depending on voicing, a major triad with an added major sixth is usually called a sixth chord , because the sixth serves as a substitution for the major seventh, thus considered a chord tone in such context.
A chord is in close harmony (also called close position or close structure) if its notes are arranged within a narrow range, usually with no more than an octave between the top and bottom notes. In contrast, a chord is in open harmony (also called open position or open structure) if there is more than an octave between the top and bottom notes. The more general term spacing describes how far apart the notes in a chord are voiced. A triad in close harmony has compact spacing, while one in open harmony has wider spacing.
Close harmony or voicing can refer to both instrumental and vocal arrangements. It can follow the standard voice-leading rules of classical harmony, as in string quartets or Bach chorales, or proceed in parallel motion with the melody in thirds or sixths.
In music, a factor or chord factor is a member or component of a chord. These are named root, third, fifth, sixth, seventh, ninth (compound 2nd), eleventh (compound 4th), thirteenth (compound 6th), and so on, for their generic interval above the root.In harmony, the consonance and dissonance of a chord factor and a nonchord tone are distinguished, respectively.
Chord factors are taken into consideration in voicing and voice leading. A chord contains exactly as many factors as it contains unique pitch names (octaves don't matter), while a voicing can have any number of voices that draw from and represent some or all the factors of a chord in various octaves. Thus, a chord with three unique pitch names always has three factors, even if some of those pitches are doubled or omitted in a particular voicing. For example, the figure to the right shows a four-note voicing of a C Major triad, which has three chord factors. The "root" chord factor (pitch name "C"), is represented twice in the voicing by voices 1 and 4 in different octaves. The chord factor called the "fifth" (pitch name "G") is represented in voice 2 (shown in red).