Riff 1: A–D–A
This progression is as about as simple as they come.
It begins and ends with an A triad and the A string is pedaled throughout; therefore, you can feel pretty confident that the progression is rooted in the key of A. (Note: In addition to analyzing the chord progression, the melody is also very helpful when it comes to determining a song’s key, or I chord; specifically, identifying where the melody ultimately resolves—that is, what note appears at the end of a verse or chorus section.
This note typically is a chord tone [root, 3rd, or 5th.
You’d be surprised by how effective this method can be.
Once we’ve established that A is the I chord, all we have to do is count up the musical alphabet from A to D: A (1), B (2), C (3), D (4).
What we discover is that D is the IV chord. And if we refer back to the section on diatonic major harmony, we know that the IV chord is major in quality, just like the D chord is here. Therefore, A–D–A is a I–IV–I progression in A.
Since this progression is diatonic to A major, we could play any major-type scale throughout: A major (Ionian), A Lydian, A Mixolydian, or A major pentatonic.
Here, A major pentatonic is used exclusively. Over the A triad, the phrase emphasizes the chord’s 3rd and 5th, C# and E, whereas over the D triad, the emphasis shifts to F# and A, which function as the 3rd and 5th of D, respectively.
Since both chords are major, we can play any major-type scale relative to the changes; for example, we could play A major over the A chord, then switch to D Lydian for the D chord.
What we’ve chosen to do here is to stick to A major pentatonic for the A chord and then switch to D major pentatonic for the D chord—a very country-esque move! Similar to the key-center phrase, this one also focuses heavily on chord tones, particularly the 3rd of each chord.
Theory break – fun time
Time to make a break.
You did a good job if you managed to reach this point and understand everything said above.
Here is an example to take a look at.
Riff 2. E-D-A
This blues-rock boogie pattern fluctuates between the 5th and 6th of each chord as it descends the E–D–A progression.
With three major chords present, how do you decides which chord is the tonic?
Well, the tip-off is the whole step between the D and E chords. If you think back to diatonic major-scale harmony, you’ll remember that the IV and V chords are major in quality and a whole-step apart.
If D and E are the IV and V chords, respectively, then A must be the tonic (I chord). Therefore, E–D–A must be a V–IV–I progression in A.
With the progression firmly rooted in A major, we could simply play the A major or A major pentatonic scale throughout.
However, because the riff has a bluesy quality to it, another option is the A minor pentatonic scale.
. This is followed in measure 2 by the root (D), b7th (C), and 5th (A) of D (implying D7), and in measures 3–4 by the root (A), b7th (G), and 5th (E) of A (implying A7). The effect (i.e., mixing major and minor tonalities) results in a very bluesy sound.
In this solo, we use an approach similar to the one used in our keycenter solo. Instead of A minor pentatonic, however, the solo starts with the E blues scale, changes to D blues for the D chord, and wraps up with a run up the extended form of the A minor pentatonic scale. Notice that the opening phrase is mimicked in measure 2.
This is a great tool for lending continuity to your solos while still nailing the chord changes.
Riff 3. A–F#m7–E–D–A
This arpeggiated riff is an extension of our previous progression, E–D– A. The only difference here is that two additional chords, A and F#m7, are tacked onto the beginning. We know a couple of things:
First, the E–D–A progression is rooted in A major. Second, this progression begins and ends with an A triad. One other thing you might recall is that F#m is the relative minor (vi chord) of A. With all of this information, we can confidently state that A–F#m7–E–D–A is a I–vi–V–IV–I progression in the key of A.
For this solo, we’re going to use the fifth-positon, three-notes-perstring A major scale exclusively. Notice that a legato pattern ascends the scale throughout the first three measures, with the root notes of the three chords (A, F#m7, and E) emphasized on beat 1 of each.
Here, we’re simply trying to emphasize the chord changes by landing on the tonic of each chord during the A major scale’s ascent. In measure 4, chord tones are emphasized on beats 1 (F#) and 3 (D) before resolving to the key’s root (A) in measure 5.
This solo starts with notes from the A major pentatonic scale (A–B– C#–E–F#) before shifting to the F# minor pentatonic scale (F#–A–B–C#–E) for the F#m7 chord change. Here’s the catch: they’re the same scale! Remember: A major and F# minor are relative scales—they share the same notes.
Notice, however, that as the chords change from A to F#m7, the phrase begins to highlight different pitches, particularly the F# note at fret 4 of string 4. In measure 3, the phrase climbs up an extended form of the E major pentatonic scale to nail the E chord change before resolving the solo via quick descent of the D major pentatonic scale in seventh position.