Quartal and Quintal Harmony Voicings

In our last lesson, you learned to construct and voice complex chords like 9ths, 11ths, and 13ths. That entire system, known as tertian harmony, is based on one core principle: stacking intervals of a third. Today, we will explore a fundamentally different system for building chords, one that is absolutely essential for creating the open, modern, and sometimes ambiguous sounds you hear in the music of bands like Polyphia.

This lesson introduces quartal and quintal harmony. Instead of stacking thirds, we will be stacking fourths and fifths. This seemingly simple change in the building block completely alters the harmonic character, moving away from the strong functional pulls of traditional harmony towards a more atmospheric and sophisticated sound. Our goal is to understand how these chords are built, how to form practical voicings on the fretboard, and how to use them within simple progressions.

A New System: From Thirds to Fourths

So far, every chord we've discussed has been tertian. A C major triad is C-E-G (a major third then a minor third). A Cmaj7 is C-E-G-B (three stacked thirds). Quartal and quintal harmony offers a new architectural plan for harmony.

• Quartal harmony builds chords by stacking intervals of a perfect fourth (5 semitones).
• Quintal harmony builds chords by stacking intervals of a perfect fifth (7 semitones).

These two concepts are closely related. A stack of fourths, if you reorder the notes, can become a stack of fifths. For example, the notes (D, G, C) represent a quartal chord. If you rearrange them as (C, G, D), they become a quintal chord. Because of this relationship, they are often discussed together as a single harmonic concept.

Let's watch a short video that introduces this idea and contrasts it with the tertian harmony you already know.

The key takeaway is that while a Cmaj7 chord sounds like C is the root, a quartal chord like (E, A, D) doesn't have a clear tonal center. Any of its notes could function as the root, which gives it a floating, open quality. This ambiguity is a feature, not a bug, and is a hallmark of modern jazz, fusion, and progressive styles.

Constructing Quartal Voicings on the Guitar

Now for the practical part: how do we build these on the guitar? A great way to start is to derive them from a scale, just as we did with tertian chords. The following reading from JazzGuitar.be explains this process using the D Dorian mode as an example.

Adapting to Your Drop F Tuning

The resources use standard tuning, but the logic is universal. Let's apply it to your Drop F tuning: F-A#-D#-G#-C#-F-A#.

An interesting feature of many guitar tunings, including yours, is that many adjacent strings are tuned a perfect fourth apart.

• A# to D# is a perfect fourth (5 semitones).
• D# to G# is a perfect fourth.
• G# to C# is a perfect fourth.
• F to A# is a perfect fourth.

This means that to stack perfect fourths across these string sets, you can often just barre your finger across the same fret. For example, playing the 5th fret across the A#, D#, and G# strings gives you D#, G#, C# — a perfect quartal triad.

However, notice the interval between your 3rd (C#) and 2nd (F) strings. C# to F is a diminished fourth (4 semitones). This is an important exception, analogous to the G-B string interval in standard tuning. To maintain a perfect fourth when crossing from the C# string to the F string, you'll need to move up one fret.

Example: Building a Quartal Chord on G#

1. Start on the G# string (4th string). Let's pick the 5th fret, which is a C#.
2. The note a perfect fourth above C# is F#. This is on the 3rd string (C# string) at the 6th fret. (5th fret is F, so 6th is F#). But we want a perfect fourth from C#, which is G#. Let's restart.
   Let's build off G# itself.
3. Start on the open G# string (4th string).
4. A perfect fourth up is C#, the open 3rd string.
5. A perfect fourth up from that is F#. This is the 1st fret on your 2nd string (F string).
6. So, playing 0-0-1 on strings 4-3-2 gives you a pure G#-C#-F# quartal voicing.

Using Quartal Chords in Progressions

These voicings can feel abstract at first. Their power becomes evident when you start using them in a musical context. They can replace standard tertian chords to add color and modernity.

A common application is in a ii-V-I progression. Let's say we are in G# major. The ii-V-I is A#m7 - D#7 - G#maj7. Instead of playing the standard 7th chords, you can substitute quartal voicings.

The video below offers an excellent, detailed guide on how to think about this substitution, introducing the vital concepts of "landing zones" (stable chords) and "passing chords" (unstable chords used for movement).

Quintal Harmony: The Other Side of the Coin

As we've discussed, quintal harmony (stacking fifths) is an inversion of quartal harmony. On the guitar, the most common quintal voicing is the power chord (root and fifth). More complex quintal harmony simply involves stacking these intervals.

For example, starting on C:

• A fifth up from C is G.
• A fifth up from G is D.
• A fifth up from D is A.

The chord C-G-D-A is a quintal tetrad. On the guitar, these wide intervals often require spread-out, two-handed, or tapped voicings, which we'll explore later in the course. For now, you can think of quintal harmony as the principle behind stacking power chords to create powerful, open-sounding riffs. A common technique in modern progressive metal is to play a power chord on the low strings and then another power chord an octave higher on the higher strings, creating a massive wall of sound built on quintal harmony.

Your Task

1. Quartal Scale Harmonization: Take the G# major scale on your 4th string (G# string). The notes are G# - A# - C - C# - D# - F - G. For each note in the scale, build a three-note quartal voicing on strings 4, 3, and 2. Write down the fret numbers for each voicing. Remember the +1 fret adjustment when crossing from string 3 to 2! This exercise will internalize the construction process.

2. Progression Makeover: Play the following common four-chord progression using standard power chords first:
   C (8th fret, A# str) - G (10th fret, F str) - A# (6th fret, A# str) - F (8th fret, F str)
   Now, replace each power chord with a 3-note quartal voicing built from the same root note. For example, for the C chord, build a C-F-A# quartal voicing. Experiment with different shapes and listen to how the character of the progression changes from rock-oriented to something more open and modern.

3. Quintal Riff: Compose a simple two-bar riff using only power chords (quintal dyads). Try stacking them by playing one power chord on your low strings (e.g., 7th and 6th strings) followed by a different power chord on higher strings (e.g., 4th and 3rd strings). This will give you a feel for quintal harmony's powerful, resonant sound.

Conclusion

You've now added a completely new system to your harmonic toolkit. Where tertian harmony provides function and direction, quartal and quintal harmony offer ambiguity, space, and a distinctly modern color.

Key Takeaways:

• Quartal and quintal chords are built by stacking fourths and fifths, respectively, as opposed to the thirds of tertian harmony.
• These voicings have an ambiguous, open sound because they lack a strong, defined root.
• On the guitar, quartal voicings can often be played with simple, straight-finger shapes due to the tuning, but watch out for string-to-string interval inconsistencies.
• In progressions, they can be used to substitute for traditional chords, adding a modern flavor, and can be thought of as "landing" or "passing" chords to create harmonic movement.

In our next lesson, we will return to the world of tertian harmony, but with a new twist. We'll explore modal interchange, the technique of borrowing chords from a parallel key (like C minor when you're in C major) to create sophisticated and emotionally rich progressions. You'll see how even traditional chords can be used in very modern ways.