- Tertian harmony involves stacked thirds for chords (triads, 7th chords)
- Quartal harmony employs stacked fourths, offering freedom and mystery
- Used by Debussy, Scriabin, and jazz for distinctive tonal exploration
- Also, check out our post on seventh chords and suspended chords
If you are reading this, chances are you are already familiar with tertian harmony – the concept of constructing chords based on third, which is used to contrast terms like quartal and quintal harmony.
In a nutshell, tertian harmony is thirds stacked on top of one another. These stacked thirds form triads and seventh chords, and these chords form the core of much of popular music and Western art music.
So then, what is “quartal harmony”?
Quartal harmony is based on fourths stacked on top of one another, as opposed to thirds, and it has a number of interesting uses.
In this article, we will elaborate further on how to create quartal harmony, as well as how to use it effectively.
Intro: What Is An Interval?
If “third” and “fourth” do not mean anything to you yet, check out this article on intervals or read on for a quick summary.
Essentially, an interval is the distance between two pitches. Intervals can be melodic (one pitch sounded after another) or harmonic (two pitches sounded simultaneously). In the case of chords, we are talking about harmonic intervals.
Intervals are identified in two ways: first, in the number of lines and spaces from the bottom note to the top note, and second in the number of semitones between the two pitches.
Pitches on the same line or in the same space are a first, or unison apart. A pitch on the line directly above a space note or in a space directly above a line note is a second above the lower pitch.
Pitches on adjacent lines or adjacent spaces are a third apart. This pattern continues, one line or space at a time.
A unison is a perfect interval if the two pitches are separated by zero semitones. If they are separated by one semitone, then it is an augmented or a diminished unison, depending on which pitch you consider to be the lower bound of the interval.
Seconds come in four different sizes, depending on the number of semitones separating them: the major second is 2 semitones, the minor second is 1, the augmented second is 3 semitones, and the diminished second is 0 semitones.
Notice that the perfect unison and the diminished second are composed of the same number of semitones, just as the augmented unison and the minor second are the same size. This overlap is why intervals are identified in two ways: by the distance on the staff as well as the distance in semitones.
Intervals on the keyboard are counted in semitones by counting every key between the bottom pitch and the top pitch.
Thirds, similarly, come in four sizes: the major third is 4 semitones, the minor third is 3 semitones, the augmented third is 5 semitones, and the diminished third is 2 semitones.
A fourth comes in three different sizes: the perfect fourth is 5 semitones, the augmented fourth is 6 semitones, and the diminished fourth is 4 semitones. The overlap with thirds in terms of interval size will prove important when we discuss applications for quartal harmony, so take note of the fact that the diminished fourth is the same size as the major third.
Building Quartal Chords
Now that we know what intervals are and how to build a fourth in terms of the number of semitones, it is time to stack some fourths on top of each other and, in so doing, build quartal chords.
Let’s begin with one pitch, C. Above that pitch, we can stack a perfect fourth, F. Above that pitch we can stack one more perfect fourth, B-flat. With that, we have created a nice, simple quartal chord.
It could just as easily be classified as a C7sus4 without the 5th but context is everything: does the chord act like a C7sus4 or is it free of the restrictions of functional harmony?
The great thing about quartal harmony is the indeterminacy of chords built from fourths. Tertian harmony has a lot of rules to it: tonic chords lead to predominant chords lead to dominant chords back to tonic chords (unless, of course, the dominant chord leads to a nice vi chord for a false cadence to spice things up a bit).
Quartal harmony is not bound by the same rules, so stepping into a progression built from quartal chords feels like stepping out into space, where the unifying gravity of tonal harmony is nowhere to be found and, instead, the inertia of intervals govern the movement of pitches relative to one another.
Why Use Quartal Harmony?
Quartal harmony can be found all over the place, from the music of Debussy to that of Emerson, Lake, and Palmer. The most prominent thread that runs through each example is a push to unmoor melody and harmony from tonal restrictions.
Schoenberg and his students, Webern and Berg–the most prominent members of the Second Viennese School–were particularly interested in resisting the conventions of tonal harmony.
This impulse is what eventually led to twelve-tone serialism, but an early effort by Schoenberg on the path to atonality (and one far more listenable to the uninitiated than his later work) is his Chamber Symphony, Op. 9.
The piece opens with a quartal chord in five-stringed instruments: A, D♯, F, B♭, E♭, A. The indeterminacy of this opening chord really sets the stage for a near-constant feeling of unsettledness that would remain throughout the piece (and that would characterize the bulk of the output of the Second Viennese School’s output).
Debussy, similarly, experiments with harmony in much of his work as a means of finding new ways of utilizing the tendencies of intervals and pitches to move towards or away from one another.
He utilizes the whole tone and chromatic scales as mechanisms in music that are void of the strong tendency of the leading tone, so that melody can float above the need to resolve that marks strongly tonal music.
All of that is simply to suggest that it is no surprise that fourths show up in his Etude 3- Pour les quartes with the effect of imbuing the piece with a sense of freewheeling exploration and no real sense of home to which the harmony need return.
Examples Of Quartal Harmony In Action
We have thus far learned the theoretical basis for quartal harmony and learned why and how some composers have used it, but enough talk! The best way to get to know quartal harmony is to listen to lots of examples. Below, you will hear some more well-known examples of quartal harmony in action.
The Tristan Chord
I have fond memories of spending at least two full lecture periods on this chord in my fourth music theory course in college. The prelude of Wagner’s masterpiece, Tristan und Isolde, opens with a quartal chord that has its own name, the Tristan chord, composed of F, B, D#, and G#.
F to B is an augmented fourth and D# to G# is a perfect fourth, while B to D# is technically a major third but it is enharmonic with a diminished fourth.
The mystery and longing communicated by this chord, and by the remainder of the prelude and the whole opera really are the pinnacle of Wagner’s exploration of harmony that never quite lets the listener relax: a full embrace of Sehnsucht and the unsettledness of the human creative experience.
Wagner’s politics were objectively bad but if you can allow yourself to treat the music separately from the man who wrote it, the quartal harmony and all of the other compositional techniques found in this prelude are highly worth the listen.
In fact, if you find yourself at the end of the prelude with three hours and 38 minutes to spare, I can’t recommend enough giving the whole opera a listen.
If you do not have three plus hours to spare but you do have three minutes, perhaps just watch this: Herbert von Karajan’s final performance with Jessye Norman singing the Liebestod from the end of Tristan und Isolde. It is easily one of the most beautiful moments in all of Western art music.
The “Mystic Chord”
The Mystic chord, also known as the Prometheus chord, is a six-note quartal chord that formed the foundation of Alexander Scriabin’s later work. It is made up of the pitches C, F♯, B♭, E, A, D and is featured most prominently in Prometheus: The Poem of Fire.
Though Arthur Eaglefied Hull called the chord the “Mystic Chord” in 1916, Scriabin called it the akkord plemory or “chord of the plemora,” and suggested it was “designed to afford instant apprehension of–that is, to reveal–what was in essence beyond the mind of man to conceptualize.
Its preternatural stillness was a gnostic intimation of a hidden otherness.” Thus the themes of mystery and of movement, or lack thereof, bound not by the order of tonal harmony but by something other persists.
Charles Ives’s “The Cage”
The 64th of Charles Ives’s collection of 114 Songs is entitled “The Cage” and, in just over a minute, it utilizes quartal harmony and a resulting sense of harmonic ambivalence to convey a leopard pacing back and forth in its cage, stopping only to eat what a zookeeper brings its way, and a child who observes this and wonders how much of life might be like that.
McCoy Tyner’s “Passion Dance”
Jazz, particularly in its especially modal pre-swing days in the early 20th century, was on a constant search for non-tertian or extra-tertian harmonic expressions and pathways.
In the mid-20th century, post-swing Jazz would cross genres to bring rock influences into the mix along with jazz staples. McCoy Tyner’s “Passion Dance” is a clear example of quartal harmony at work in the left hand and the right hand of the piano part.
Miles Davis and Bill Evans in “So What”
One of the best-known, if not the best-known example of modal jazz, “So What” opens with the “So What” Chord, spelled out E, A, D, G, B, three perfect fourths and a major third (enharmonic with a diminished fourth).
This is the sort of harmonic structure that works nicely in modal jazz, freed from the tonal superstructure, the musician can explore harmonic and melodic motion at the scale of individual pitches and intervals.
Wrapping Up
Whether a piece of music is structured entirely out of quartal harmony or quartal chords make for a temporary respite from the strictures of tonal, tertian harmony, quartal harmony offers a great deal of possibility to a composer.
The indeterminacy and mystery implied by these chords are the sort of sound you cannot get out of typical triads. For that reason, you might as well add them to the toolkit to know where to reach (next time your music calls for something a little different).
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