Welcome to the latest installment of Chord by Chord, a series designed to build your fretboard familiarity and understanding of harmony. In previous lessons, I showed you the four basic triad types—major, minor, diminished, and augmented—and this time you’ll learn the first chord beyond a triad, a seventh chord.
There are different types of seventh chords, and the dominant seventh is perhaps the most commonly used in popular music. Often referred to simply as the seventh chord, it takes a major triad and adds the flatted seventh. So a D major triad is spelled D F# A (Example 1), and a D7 chord is spelled D F# A C (Example 2).
Now let’s create D7 chords from various D voicings, first with the open D chord. As shown in Example 3, to change it to D7, all you have to do is replace the D on string 2 with the C (the flatted seventh) on the same string.
Example 4 shows some barred voicings. These chords are often played on just strings 2–5. You might also try them with fingerpicking, using your thumb on string 5 and index, middle, and ring fingers on strings 3, 2, and 1, respectively.
In Example 5 we have a less common D voicing, which can be modified to make a more common D7 shape. Example 6a takes you up to a barre chord in tenth position. All you have to do to get to a D7 chord from the D is remove your fourth finger. A variation on Ex. 6a is shown in Example 6b. This D7 shape is the same, but by adding your fourth finger to string 2, fret 13, you are doubling the flatted seventh that is also played an octave lower, on string 4, fret 10.
Example 7 is identical to Ex. 3, but with each fretted note moved up an octave (12 frets), for a more dramatic sound—a voicing that will be more difficult to play if you’re on a guitar with a 12th-fret neck junction.
If you’ve done the work, now you know how a D7 chord is constructed and how to change various D shapes to D7. Van Morrison’s “Brown Eyed Girl” is a well-known song that makes use of a D7 chord, as well as a handful of others that you should already know.
Stay tuned for next time, when you’ll learn a bunch of G7 shapes.