Chapter 11:
Seventh chords and drop voicings
What are seventh chords?
Seventh chords are triad chords with an additional “stacked third” on top, which is always some kind of seventh interval. See Chapter 6. Introduction to Western harmony for more information about stacking thirds.
The seventh interval adds some dissonance to the triad chord, but not too much. It’s a familiar sound to Western ears, and a good way to add a little tension and interest to a chord.
Types of seventh chord
There are five types of seventh chord used in euroclassical harmony.
| Chord type | Intervals | Symbol (on C) | Notes (on C) |
|---|---|---|---|
| major seventh | R 3 5 7 | Cmaj7, CΔ7 | C-E-G-B |
| dominant seventh | R 3 5 b7 | C7, Cdom7 | C-E-G-Bb |
| minor seventh | R b3 5 b7 | Cm7, Cmin7, C-7 | C-Eb-G-Bb |
| half diminished | R b3 b5 b7 | Cm7b5, Cø | C-Eb-Gb-Bb |
| diminished seventh | R b3 b5 bb7 | Cdim7, C°7, C° | C-Eb-Gb-A |
The first four are harmonized from the major scale, as described in Chapter 8. Major key harmony. The V chord is a dominant seventh, the vii chord is half diminished, and the other major and minor chords are major sevenths and minor sevenths. The half diminished chord is sometimes called a “minor 7 flat 5”.
The diminished seventh chord arises in minor harmony, when raising the root of the bVII chord a semitone to create the leading tone. See Chapter 9. Minor key harmony for details.
The bb7 interval may be unfamiliar. It’s called a “diminished seventh” interval, the result of lowering a minor seventh by one semitone. It’s enharmonically equivalent to a major sixth.
About seventh chord voicings
The more notes we add to a chord, the fewer playable chord grips are available.
Seventh chords are most usefully organized around three basic shapes, one each with roots on the 6th, 5th, and 4th strings. These are essentially the E, A, and D CAGED shapes.
Seventh chord grips are often categorized by their “voicing”.
Open voicings are more playable
Look at a closed voice seventh chord in root position on the fretboard, like the following major seventh chord.
While it may be possible to grip that chord shape, it’s probably not going to be comfortable. And most seventh chords have a b7, making them even less playable.
As shown in the following figure, the solution is to play the chord tones in more comfortable locations.
In this example, the 7 is the same pitch at a more convenient location (a unison), and the 3 and 5 have been raised an octave.
Raising the chord tones an octave creates an open voicing, which changes how the chord sounds. Fortunately, seventh chords usually sound better in these open voicings. The closed voicings can sound “muddy”, and opening them up can make them sound lighter and more spacious.
Drop 3 voicing
The open voicing shown above is an example of a “drop 3” voicing.
The reason it’s called a drop 3 voicing is a bit complicated, and not particularly important to understand. See “More about drop voicings” later in this chapter for details.
For simplicity, we just need to remember a few things about drop voicings on guitar.
Drop 3 voicings on guitar have the following properties.
- A 6th-string root (mostly, but 5th string roots are also possible).
- A signature string skip over the muted 5th string.
- A
R-7-3-5voicing, third and fifth factors raised an octave.
Drop 2 voicing
These are examples of “drop 2” voicings.
Drop 2 voicings on guitar have the following properties.
- A 5th-string or 4th-string root.
- No string skip, on 4 contiguous strings.
- A
R-5-7-3voicing, the third factor raised an octave.
Chord grips
E shape (drop 3)
A shape (drop 2)
D shape (drop 2)
More about drop voicings
In drop 2 voicings,
the second note from the top of the chord is dropped down an octave.
This is typically applied to the second inversion (5-7-R-3),
so the root note remains in the bass:
R-5-7-3.
In drop 3 voicings,
the third note from the top of the chord is dropped down an octave.
This is typically applied to the third inversion (7-R-3-5),
so the root note remains in the bass: R-7-3-5.
After these common drop 2 and drop 3 voicings have been mastered, it can be interesting to explore drop voicings of other inversions, creating chords with notes other than the root in the bass.