Often when guitarists see a minor 7 chord or a minor tonal center, they’ll jump to the obvious, time-tested and ever-so-powerful corresponding minor pentatonic scale. But with some more theory under the hood, you’ll find the corresponding minor 7 arpeggio is another option. The same reflex applies to a major 7 chord or a major tonal center, associated with a major pentatonic and a major 7 arpeggio. With some basic theory, we can mix and match both chord types, incorporate them into minor or major pentatonic scales, and create some unconventional sounds to use in melody writing or soloing.
Let’s break down the theory first: A beautiful Cmaj7 chord (C–E–G–B or 1–3–5–7 of the C major scale) is your frame of reference. Now let’s flip things around and take a minor 7 chord, but have the root start on the 3 of the original major 7 chord. In other words, Em7 (E–G–B–D) will translate to 3–5–7–9 in the key of C.
If we keep flipping things around, we can create a major 7 chord starting on the 5 of Cmaj7. We now have Gmaj7 (G–B–D–F#). Its chord tones are 5–7–9–#11 in the context of the key of C.
One final flip: A minor 7th chord with the root starting on the 7 of Cmaj7 creates a Bmin7 (B–D–F#–A) which translates into 7–9–#11–13 in the key of C.
See a pattern here? For every new chord superimposed onto the original chord, one additional tension appears, and we end up with a 9, #11, and 13 on top of the original root, 3, 5, and 7. This spells out a Lydian mode, although the way the notes are organized—or rather, disorganized—makes it seem less obvious than a regular suite of numbers, such as root, 2, 3, #4, and so on.
Let’s apply this concept by using those superimposed four-part chords as arpeggios. A very interesting fingering for any four-part chord is having your root on the 5th string and following a 2–1 pattern. This creates the fingerings in Fig. 1 and Fig. 2. Check out how you have two notes played on the 5th string, one on the 4th, and so on. This creates the 2–1 pattern.
You can approach those fingerings with different picking techniques, but one that I favor is combining sweep picking with hammer-ons and pull-offs. That said, there is no one right way to do it. One tip that helped me is to start with an upstroke and then continue with downstrokes. From high to low, do the opposite (think upstroke first). It feels like giving your whole run a kick-start.
In Fig. 3, all four arpeggios associated with Cmaj7 (Cmaj7, Em7, Gmaj7, and Bm7) are played over a Cmaj7 tonal center. The first arpeggio goes up, the second goes down, third up, fourth down. This is a great exercise to learn how to efficiently move around the fretboard.
Fig. 4 is a bit of a speed-freak moment as we chop those arpeggios in half and only keep the top part, each starting on their own 7th degree.
We mix and match different sections of arpeggios in Fig. 5. In order to keep things interesting as we wind our way up the neck I threw in some triplets while changing the direction in a few spots for good measure.