IN LAST MONTH’S LESSON [“Diminished Transformers,” June 2010 GP], we explored the concept of unfolding a diminished 7 chord into four dominant 7s, an idea we can attribute to Pat Martino. We compared this process to manipulating Transformers from their robot form into something new and different. In this lesson, we’ll take this chord-generating technique even further.

For starters, let’s revisit the basic principle: If you lower a note within a diminished 7 chord by a half-step, you’ll get a dominant 7 chord with the lowered note as its root. Because lowering any of the diminished 7’s four notes will generate a new dominant 7, one diminished 7 voicing spawns four dominant 7s.

Look at Ex. 1, which has a Gdim7 as the first voicing. Pluck Gdim7—it’s our diminished 7 transformer in this lesson—then lower the root on string six by one halfstep to F#. As shown in the second grid, this lowered note becomes the root of F#7. At the bottom of the grid, you’ll see each tone’s function in this new chord. To help you visualize the root, it’s shown as a hollow circle on every chord grid.

After strumming Gdim7 again, drop the note on string four by one half-step and you’ll get an Eb7. Repeat the process lowering the notes on strings three and two to generate A7 and C7 chords, respectively. We’ve now created four dom7 voicings from a root-position dim7 voicing.

Moving a diminished 7 voicing three frets higher brings you to its nearest inversion. Ex. 2 begins with a 1st-inversion Gdim7, which, like its root-position predecessor, spawns four dom7s. We get new fingerings of the same four chords we generated in Ex. 1— F#7, Eb7, A7, and C7—except now they’re in a different order.

Examples 3 and 4 carry us through the 2nd and 3rd inversions of Gdim7 and yield two more sets of our dom7 chords. This means we now have four ways to play F#7, Eb7, A7, and C7. Some of these 16 dom7 chords are old friends, but it’s likely some will be new, or at least, less familiar to your fingers. And because these voicings are moveable—they contain no open strings—every one of them can be played chromatically up and down the fretboard. Wow, a plethora of dom7s!

But what’s the point? Beyond having a wealth of dominant 7 possibilities at your fingertips, there’s an excellent reason for spawning so many dom7s from diminished 7 transformers: A dominant 7 chord makes a superb platform for generating a wide variety of other chord types. Let’s take just one dom7 fingering to make this point—the A7 we first encountered in Ex. 2. Because it’s conveniently positioned in the middle of the fretboard, raising or lowering one or two notes in this A7 fingering is easy.

Look at Ex. 5 and the 1-b7-3-5 A7 voicing in the upper left grid. If you lower the b7 to 6, you get A6. Or—returning to A7— lower the 3 to b3 to generate Am7. Or combine the 6 and b3 to get Am6. See what’s happening? By sliding one or two notes up or down from our starter A7, we get the 12 chord types shown here. In other words, from a humble A7 we can wrangle A6, Am7, Am6, Am7b5, A7b5, Amaj7, Amaj9, A9, A7sus4, A7#5, and A13. And with a little investigation, you’ll find other chords too.

Let’s recap:
• We start with a single dim7 fingering.
• Lowering any one note of this dim7 yields a dom7 voicing, for a total of four dom7s from one dim7.
• Moving along the fretboard through the given dim7’s inversions (root, 1st, 2nd, and 3rd) generates a total of 16 dom7 chords.
• Raising or lowering one or two notes within a dom7 chord yields other chord types, such as m7, maj7, 7b5, and so on.
• Because we’re working with moveable forms, every chord shape we uncover can be played in all 12 keys.

At this point, we have a wonderful alternative to a chord dictionary. If you recall, in last month’s lesson we looked at four dim7 fingerings on different string sets. In this lesson, we walked one of these dim7s through its inversions. To get a thorough workout, march the other three through their inversions. Simply start with a dim7 transformer, grind out the dom7s in each inversion, tweak the dom7s as we did in Ex. 5 to create other chord types, and you’ve got dozens and dozens of useful voicings all over the fretboard. No doubt you’ll like the sound of some but not others, and you’ll also find some are easy to play while others are very difficult. Write down the voicings you like, and discard the rest.

It takes time to explore the fretboard this way, but such is the price of mastery. To avoid being overwhelmed, just ease into the concept, and whenever you get an “a-ha” moment, remember to thank Pat Martino.

CHORD INVERSIONS

A seventh chord is composed of four notes—the root, plus the third, fifth, and seventh tones of a major scale starting from the same root. This 1- 3-5-7 arrangement can be altered according to specific formulas to create a variety of chord types. For instance, a dominant 7 chord has a formula of 1-3-5-b7 and a minor 7 chord has a 1-b3-5-b7 formula. When the root is the lowest note, the chord is—not surprisingly—in root position. But there are other ways to stack the notes. When you move the root up an octave, the chord is in its 1st inversion (3-5-7-1). Now move the 3 up an octave, and you get a 2nd-inversion seventh chord with the 5 as the lowest note (5-7-1-3). Moving the 5 up an octave yields a 3rd-inversion seventh chord (7-1-3-5).

In each of these inversions, the notes remain within a single octave; this is called a close voicing. In an open voicing, selected notes are shifted to lower or higher octaves to create seventh-chord harmony that extends beyond an octave.

Andy Ellis hosts The Guitar Show weekly radio program, which streams online. Visit theguitarshow.com for details.