Download Seventh Chords

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Seventh and Added-Sixth Chords: Overview
We first learned about seventh chords as a 4-note tertian harmony, or a triad with a
interval added. We also spent a fair amount of time on dominant seventh chords as we
worked on our part-writing. We have also mentioned that there are other types of seventh
chords, and you may already know some of these.
7th
So now it’s time to ask just how many types of seventh chords there are, and how to
spell and label them. If we agree that seventh chords are simply triads with an added 7th,
then that gives us eight possible ingredients to work with: the four types of triads, and the
four 7th intervals shown in Figure 1.
Figure 1: Triads and Sevenths
The augmented 7th is not useful, because it is enharmonic to the perfect octave.
Further, the diminished 7th interval is often enharmonically spelled as a major 6th. When
this happens, the chord that results is called an added-sixth chord.
Combining the four triad types with the major seventh, the minor seventh, and the
diminished 7th/major 6th gives us 12 possible chords. Here are the possibilities in the key of
C, with their popular symbols:
Figure 2: Twelve Possible Seventh and Added-Sixth Chords
Some of these are very common; others (like the diminished-major 7th) are rarely
used. The one chord that is almost never used is the augmented triad with a major 6th,
which sounds like an inverted minor/major 7th and has no tonal function.
Added-Sixth Chords
Adding a major 6th onto a triad adds some color without adding a “true” 7th, which
creates a tendency tone. Added-sixth chords were rather common in late 19th-century
music, including a lot of American standard tunes that formed the basis of the jazz
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repertoire. Not everyone considers added-sixth chords to be a type of seventh chords, but I
like including them here because they are quite common, and I haven’t heard any better
way to explain them! Another aspect of added-sixth chords is that they can be seen as
inversions of other seventh chords, as shown in Figure 3.
Figure 3: Added-Sixth Chords as Inverted Seventh Chords
Added-sixth chords can also occur when a chromatically-moving line is placed
against a tonic triad. This creates slight color variations in a chord that is not really going
anywhere. Jazz musicians call this technique CESH, for Chromatic Elaboration of Static
Harmony. This technique is common in many styles including classical, jazz, and rock.
Figure 4: Chromatic Elaboration of Static Harmony (CESH)
Seventh Chords in Key Context
The major, natural minor, harmonic minor, and (ascending) melodic minor scales
each produce their own particular set of diatonic seventh chords. Note the subtle
differences between the popular chord symbols and the traditional Roman numeral
analysis:
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Figure 5: Seventh Chords from the Major Scale
Figure 6: Seventh Chords from the Natural Minor Scale
Figure 7: Seventh Chords from the Harmonic Minor Scale
Figure 8: Seventh Chords from the Melodic Minor Scale
We typically divide these chords into categories based on how commonly they are
used in traditional music: dominant sevenths (V7), leading-tone sevenths (viiø7 and viio7)
and non-dominant sevenths (everything else). Over the next few chapters we will look at
usage and part-writing concerns for each of these types of chords. There is one other
seventh chord type that we did not cover here—seventh chords with a lowered fifth, or
“flat-five” chords. These chords do not arise from the triadic system and will be dealt with
later in a discussion of altered dominant chords. The chart on the next page provides a
summary of all of the seventh and added-sixth chords, along with their most commonlyused popular chord symbols.
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Figure 9: Chart of Seventh and Added-Sixth Chords
Triad
Major
Major
Major
Minor
Minor
Minor
Augmented
Augmented
Augmented
Diminished
Diminished
Diminished
Major (♭5)
Seventh
M7
m7
M6
M7
m7
M6
M7
m7
M6
M7
m7
d7
m7
Popular Name
Major 7th
Dominant 7th
Major 6th, added-6th
Minor-major 7th
Minor 7th
Minor 6th
Augmented-major 7th
Augmented dominant
(not used)
Diminished-major 7th
Half-diminished 7th
(“Fully”) Diminished 7th
Dominant flat-five
Symbols
M7, maj7, ∆7
7
6, M6, add6
m(maj7), m(∆7)
m7, mi7, –7
m6, mi6, –6
+ (maj7), + (∆7), maj7(#5)
+ 7, 7(#5)
o(maj7), o(∆7)
ø7, m7(♭5)
o7
7(♭5)
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