Harmony Guitar Lines: Four Ways to Craft Twin-Guitar Leads Like the Eagles, Allmans and Others

Create great-sounding harmony lines for classic-style twin-guitar leads, solos and fills using intervals of thirds, fourths, fifths and sixths.
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What do classic bands like the Beatles, the Allman Brothers, the Eagles, Steely Dan, Boston, Iron Maiden, Judas Priest and the Scorpions have in common?

They’re all known for their two-part-harmony guitar solos. Okay, so the Beatles mainly did it in “Nowhere Man” and “And Your Bird Can Sing,” but they’re among the most memorable solos in the group’s catalog—and harmony soloing is why!

Whether your band has two guitarists or you use a harmonizing device, twin-guitar harmony can be a compelling device for fortifying your solos. An undeniable attention-grabber, it not only beefs up your tone (and doubles the volume) but also adds a walloping impact to your melodic lines, licks and scale sequences.

In this lesson, we’re going to look at four ways you can create great-sounding harmony lines to create classic-style twin-guitar leads, solos and fills using intervals of thirds, fourths, fifths and sixths.


As in vocal harmony, the most common form of twin-guitar harmony is derived from diatonic 3rds.

What are diatonic 3rds? They are the pairing of two notes within the same scale that are two scale tones apart.

For example, in the key of C major (C D E F G A B), the tonic (C) and the note two scale steps above it (E) are a diatonic 3rd apart. Likewise, the D and the F represent a diatonic 3rd. Continue this note-pairing process up the scale and you have the C major scale harmonized in thirds (E/C, F/D, G/E, A/F, B/G, C/A, D/B).

Of course, you can play these intervals by yourself, but when the notes are divvied up between two players, the tone and the quality of the intervals are more distinguishable. Splitting up the parts also promotes easier access to guitar nuances, such as bends, hammers/pulls, slides and vibrato.

Let’s take a look at some practical applications of 3rds.

FIGURE 1A is in the key of C. The bottom line (low note of each dyad) is the original melody. The top line (top note of each dyad) is the harmony.


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The same goes for FIGURE 1B, except it’s in the key of E minor. (The main melody is generally voiced on the bottom in 3rds harmony.)


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FIGURE 1C harmonizes a common “groups of 4” sequence in A minor. This one’s easy to extend—both players simply continue the sequence all the way down the pattern.


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Here are a few tips for developing your 3rds harmony skills. One, have you partner play the melody of a simple song (nursery rhymes and Christmas carols work well for this) while you harmonize it in 3rds. Two, designate a key, have your partner construct a simple melody, and you try to harmonize it in 3rds.


As you continue your 3rds harmony explorations, you’ll eventually run up against some problems. Sometimes the harmony just doesn’t seem to fit. Often in these cases, 4ths can be your champion dyads.

It’s certainly possible to harmonize scales in 4ths, but we don’t need to go there. Just keep in mind that when your harmony line doesn’t quite fit against the melody, you should try to substitute a perfect 4th (two and a half steps above the melody note).

Check out FIGURE 2A. Essentially, it’s an E major melody harmonized in 3rds, but the second and third notes are harmonized in 4ths. Notice that these “substitute” harmony notes (E and F#) also belong to the key of E. Thus, we’re using diatonic 4ths as an alternative to 3rds.


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As an experiment, try playing the example staying with 3rds. Hear the difference? The 4ths seem to be more in keeping with the tonality of the E chord.

Fourths are also an integral part of pentatonic harmony. The pentatonic scale is a five-note scale, so it doesn’t play by the rules of traditional diatonic harmony, However, if you sift throughout the B minor pentatonic scale (B D E F# A), for instance, you can match up three sets of 3rds (D/B, F#/D, A/F#) and four sets of 4ths (E/B, A/E, B/F#, D/A).

Granted, this can be a very hit-and-miss exploratory process, but the results can be well worth the struggle. Play through the B minor pentatonic examples in FIGURE 2B, and you may find the concept easier to grasp on the fretboard than it is on paper.


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Another common form of two-part harmony involves diatonic 6ths. Sixths harmonies are constructed much like 3rds, except that with 6ths the main melody line is usually on top, with the harmony voiced a 6th below. From this perspective, 6ths are just like inverted 3rds. In other words, the 3rds dyads mentioned at the start of this lesson would be converted to C/E, D/F, E/G, F/A, G/B,, A/C and B/D.

Confused? Well, let’s look at a couple of examples.

FIGURE 3 is based on a slightly sequenced run in E harmonic minor (E F# G A B C D#) (top line). Instead of going with diatonic 3rds voiced above the melody, it takes those would-be 3rds and drops them down an octave. This sets them a diatonic 6th below the melody.


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Just as 3rds and 4ths often pair up in complementary teamwork, 6ths and 5ths can also form common bonds. The G minor example in FIGURE 4 reveals just how potent combinations of 5ths and 6ths intervals can truly be.


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