NOT ONLY IS PAT MARTINO AN amazing guitarist, he’s one of the most original thinkers to pick up the 6-string. In the inspiring “Ten Things You Gotta Do To Play Like Pat Martino” [Jan. 2010 GP], Jesse Gress reminds us of Martino’s many insights regarding harmony, music theory, and the fretboard. One idea in particular—how you can unfold a diminished 7 chord into four dominant 7s— offers a potent way to explore chordal harmony and view the fretboard from a new perspective. Martino explains this theory in his Creative Force DVD [Alfred Publishing] and currently out-of-print books, but many of us haven’t yet had the opportunity to internalize the concept. No time like the present, right?
First, let’s review the process and then apply it to the fretboard. Here’s the premise: If you lower any note within a diminished 7 chord by a half-step, you’ll get a dominant 7 with the lowered note as its root. Have you ever unfolded a Transformer robot? It’s a similar idea, only instead of a robot morphing into a sports car or tank, we have a diminished 7 transforming into a dominant 7.
Check it out: A diminished 7 comprises four notes. Because lowering any of the notes will generate a new dominant 7, one diminished 7 voicing spawns four dominant 7s. This is more than an intellectual curiosity. By playing with “diminished transformers,” you can:
• Visualize the fretboard in new ways.
• Discover new dominant 7 voicings.
• Strengthen your understanding of music theory.
• Sharpen your ability to hear harmonic motion.
• Generate new fretting- and pickinghand exercises.
Let’s use a Cdim7 chord as the starting point—our diminished transformer. Ex. 1 shows a Cdim7 voicing on the inner four strings. Play Cdim7 and then lower the note on string five (C) by one half-step. Voilà— B7. Now return to Cdim7, strum it to recalibrate your ear, and then lower the note on string four (Gb) by one half-step. This becomes the root of our next dominant 7, F7. Continue the process, first playing Cdim7 and then transforming it into Ab7 and D7. As you work through this example, notice how each chord’s root is shown as a hollow circle on the grid, and every note’s function is listed below the grid.
The next step is to create musical exercises from the four dominant 7s to give your hands and ears a workout. It’s important to emphasize the root of each dom7—this helps you “hear” it correctly. One way to accomplish this is to create an arpeggio that starts and ends with the root. Ex. 2 illustrates a few of the many possibilities.
In Ex. 3, we use a Cdim7 voiced on the top four strings as the transformer. Again, individually lowering each note in this voicing yields F7, B7, D7, and Ab7.
So far, we’ve been using dim7s voiced on adjacent strings, but the transformer process works equally well with voicings that occur on split string-sets, as shown in Examples 4 and 5. Several of the resulting dominant 7 forms will be immediately familiar in these examples, but there are some unexpected treats, such as the Ab7 forms that have a 3 as their lowest tone. These particular inversions make great passing chords and come in handy when you want to spice up a 12- bar blues.
There’s another hip angle to explore with diminished transformers, and we’ll investigate it in next month’s lesson. Meanwhile, turn the dom7s in Examples 3-5 into picking exercises, as we did in Ex. 2. Then look for ways to incorporate some of these dom7 fingerings—especially those that are new to you—into songs.
DOM7 & DIM7 FORMULAS
Every chord type has a formula that’s derived from a major scale— our musical yardstick. For instance, the formula for a dominant 7 chord is 1, 3, 5, b7—the first, third, fifth, and lowered seventh tones of a major scale. Apply this formula to a Cmajor scale (C, D, E, F, G, A, B, C), and you get C, E, G, and Bb— C7’s component notes.
The formula for a diminished 7 chord is 1, b3, b5, bb7. Thus, Cdim7 consists of C, Eb, Gb, and Bbb. Sonically, a bb7 note is the same as a 6, so many musicians choose the latter when spelling a dim7 chord, simply because it’s less of a mouthful. Using this informal approach, we’d identify Cdim7’s component notes as C, Eb, Gb, and A. — AE
Andy Ellis hosts The Guitar Show weekly radio program, which streams online. Visit theguitarshow. com for details.