Excerpted from The Way Music Works | BY GRETCHEN MENN
While you’re familiar with the basic major and minor triads, any numbers following a chord intimidate you.
Combine your existing knowledge with a little bit of additional theory. Work through a series of exercises to form a foundation for understanding and using seventh chords. Then you won’t bat an eye at the harmonies in such songs as Led Zeppelin’s “Going to California,” Eric Clapton’s “Tears in Heaven,” or the Beatles’ “Yesterday.”
Start with the concept
The basic concept for seventh chords is simple enough: any number following a chord indicates the note that is to be included in the basic triad to form a more colorful harmony. If you see a 7, this means that in addition to the notes of the triad, you’ll also include the note a seventh above the root. Or, if you find it easier to count backwards, just go one step down (whole or half, as the case may be) from the root. The most common seventh chord types are dominant, major, minor, half diminished, and diminished. In this introductory lesson, you’ll work with the first three types. Here’s how they are constructed:
If you see a seven following a chord with no further qualification, it’s a dominant seventh chord—a major triad that includes a minor seventh. It is often simply called a seventh chord and indicated with a 7 following the root name, for example, F7. To build a dominant seventh chord, take any major triad, and add a minor seventh above the root. An easy way to find the minor seventh is to go down a whole step from the root. So if the root is F, a whole step down is Eb, and that F7 chord is spelled F (root), A (major third), C (fifth), Eb(minor seventh).
A major seventh chord is a major triad that includes the major seventh. An easy way to find the major seventh is to go down a half step from the root of the chord. If the root is F, a half step down is E. An Fmaj7 chord (also written FM7 or F∆7) is spelled F (root), A (major third), C (fifth), E (major seventh).
To get a minor seventh chord, add the minor seventh to a minor triad. An Fm7 chord (also written F-7) contains the notes F (root), Ab (minor third), C (fifth), and Eb (minor seventh).
Transform familiar triad shapes into dominant sevenths
Start by reviewing major and minor triads. Ex. 1 takes you through an F-major chord in various inversions, and Ex. 2 does the same, but with F-minor chords. Remember, a minor triad can be easily built from its major counterpart by simply moving the third down a half step.
It’s also easy to transform major triads into dominant seventh chords. The triads here are all four-note voicings, which means one note in each voicing is doubled. So by moving one of the doubled notes to the seventh, you can create a complete seventh chord. In Ex. 3, start with the familiar F major triad, followed by its associated F7 voicing. This first chord in the series has two Fs, so move the lower of the two—the F on the D string—down a whole step, to Eb.
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For the next inversion (Ex. 4), move the higher of the two Fs, falling on the B string, down to Eb. If you’re unsure why I told you to choose that F, rather than the lower one, try it the other way, and you’ll find it’s virtually unplayable unless you have enormous hands or are very high on the neck.
In Ex. 5, the fifth (C) is doubled; move the lower C up to Eb. Then, in both Ex. 6 and Ex. 7, move the upper root (F) down to Eb. Note: Not all of these grips are playable on non-cutaway guitars. But learn all the voicings regardless, as when you move to other keys, they will fall at different places on the fretboard, rendering them more or less useful.
Repeat the process, using major seventh and minor seventh chords
To create Fmaj7 chords from F triads, you’ll do the same thing you did in Exs. 3–7. But, as shown in Ex. 8, move one note in each F chord to E, rather than Eb, to form its major seventh sibling. Similarly in Ex. 9, you can transform minor triads into minor seventh chords by moving one of the doubled notes in each triad to Eb.
It won’t hurt to memorize these chords for use on the fly. But knowing how you built them will help you learn to engineer harmonies all over the neck, and move smoothly between them. Now go make these your seventh chords your own, and write some music with your new vocabulary!
Gretchen Menn is a guitarist and composer based in the San Francisco Bay Area. She writes, records, and performs original music and is a member of the popular Led Zeppelin tribute band Zepparella. gretchenmenn.com