Quartal harmony is a harmonic technique in music theory and composition based on the interval of a perfect fourth, rather than the traditional tertian (third-based) chords of common practice tonality. It is commonly associated with 20th-century classical music, jazz, and various folk traditions, offering a distinct, open, and often ambiguous sonority that contrasts with the stacked thirds of major and minor triads. The term encompasses both chord structures built by stacking fourths and melodic frameworks derived from fourth-based intervals.

1 Historical origins

1.1 Early uses in medieval and Renaissance music

The perfect fourth was treated as a consonance in early medieval organum (e.g., parallel organum at the fourth). In Renaissance polyphony, however, the fourth was increasingly regarded as a dissonance requiring preparation and resolution when used above the bass. Isolated instances of chords built on fourths appear in pieces such as the *Rota* (c. 1260) and in certain works by Guillaume de Machaut, but these are not systematic. Folksong traditions in Eastern Europe, the Balkans, and East Asia long employed fourth-based intervals in both melody and drone-based harmony.

1.2 Revival in late 19th- and early 20th-century classical music

1.2.1 Claude Debussy and impressionism

Claude Debussy’s music after the 1890s frequently uses chords formed by parallel fourths, often to evoke a shimmering, static quality. Examples include the opening of *Prélude à l'après-midi d'un faune* (1894) and the piano piece *Voiles* (1910). Debussy employed such sonorities not as functional progressions but as coloristic blocks, weakening the gravitational pull of traditional tonality.

1.2.2 Russian composers (Scriabin, Stravinsky)

Alexander Scriabin’s later works, particularly his *Mystic Chord* (a six-note chord stacked in fourths: C–F♯–B♭–E–A–D), exemplify quartal construction as the basis for an entire harmonic system. Igor Stravinsky used fourth-based chords in *The Rite of Spring* (1913) and *Les Noces* (1923), often in percussive, ostinato-like patterns. These composers expanded quartal harmony into a deliberate structural principle.

2 Theoretical foundations

2.1 The perfect fourth as a building block

2.1.1 Interval structure and inversion

A perfect fourth spans five semitones (e.g., C–F). Its inversion is a perfect fifth (seven semitones). In quartal harmony, chords are built by superimposing perfect fourths (e.g., C–F–B♭–E♭). Because the fourth is not a stable root-interval in traditional theory, quartal chords are often ambiguous in root identity and are frequently left incomplete or altered.

2.1.2 Comparison with tertian harmony

Tertian chords stack major or minor thirds, producing triads and seventh chords with clear root/third/fifth hierarchies. Quartal chords lack the third’s defining major/minor quality, resulting in a more neutral, open sound. Their lack of a strong root progression makes them naturally suited to static or modal contexts.

2.2 Chord types in quartal harmony

2.2.1 Pure quartal chords (stacked fourths)

These consist exclusively of perfect fourth intervals, for example:

  • Three voices: C–F–B♭
  • Four voices: C–F–B♭–E♭
  • Five voices: C–F–B♭–E♭–A♭

Pure quartal chords often contain the same intervals as extended tertian chords (e.g., C–F–B♭ is an inversion of a C7sus4 chord), but the intent is quartal stacking.

2.2.2 Mixed quartal and tertian chords

In practice, many composers and improvisers combine fourths with thirds, seconds, or tritones. For instance, a chord may have a fourth-stacked core with a tertian extension (e.g., C–F–B♭–E–G). These hybrids allow greater harmonic color while retaining an open quartal flavor.

2.3 Voicing and spacing considerations

Quartal chords are typically voiced in close position or spread across multiple octaves. Dense voicings (with fourths in the lower register) can sound thick or muddy; wider spacing (e.g., left hand playing a fourth, right hand playing higher fourths) clarifies the sonority. In orchestration, quartal chords are often distributed among different instrument families to avoid excessive dominance of one register.

3.1 Emergence in modern jazz (McCoy Tyner, Bill Evans)

In the late 1950s and 1960s, pianists McCoy Tyner and Bill Evans pioneered quartal voicings as a core element of modern jazz harmony. Tyner’s work with the John Coltrane Quartet (e.g., *A Love Supreme*, 1965) frequently uses left-hand fourth-based chords over pedal points, creating a powerful, modal energy. Evans’s voicings, as heard on *Kind of Blue* (1959), are more delicate, often mixing fourths with thirds in his characteristic “rootless” left-hand patterns.

3.2 Quartal harmony in guitar comping

Jazz guitarists such as Jim Hall, John Scofield, and Pat Metheny commonly employ quartal chords in comping. The guitar’s standard tuning (E–A–D–G–B–E) makes it easy to form fourth-based shapes on the lower strings. Common voicings include three-string fourth stacks (e.g., A–D–G) and larger “so what” clusters (see 3.3.1). Quartal comping provides a sparse, open texture that complements soloists.

3.3 Relationship to modal jazz

3.3.1 So What chord and voicing techniques

The “So What” chord, named after Miles Davis’s 1959 composition, is a two-hand piano voicing: left hand plays a fourth (e.g., E–A), right hand plays a D–G–C triad. This yields a Dm11 sonority built on stacked fourths (D–G–C–F–A–E). It became a staple of modal jazz, demonstrating how quartal voicing can highlight a single mode (here, D Dorian) without functional progression.

3.3.2 Improvisation over fourth-based structures

When improvising over quartal harmony, musicians often use fourth-based melodic patterns, pentatonic scales, or the parent mode of the chord (e.g., Dorian for a minor quartal chord). Because quartal chords lack leading tones, scalar playing often replaces chord-tone targeting. Many jazz improvisers also superimpose fourth-based lines over conventional progressions to produce deliberate harmonic ambiguity.

4 Contemporary classical and experimental uses

4.1 Serial and post-tonal approaches

Composers such as Arnold Schoenberg and Anton Webern occasionally used quartal chords within twelve-tone rows for their symmetrical properties. Later, Olivier Messiaen incorporated fourths in his “modes of limited transposition.” In post-tonal music, quartal harmony often functions as a block in a pointillistic or textural context, with no tonal implications.

4.2 Quartal harmony in film scoring

Film composers frequently employ quartal sonorities to create a sense of mystery, vastness, or timelessness. John Williams uses fourth-based motifs for the Force in *Star Wars* (e.g., the opening of “Binary Sunset”). Hans Zimmer and his collaborators (e.g., in *Gladiator*, *Inception*) often layer quartal strings and brass over pedal points to produce epic, unresolved tension.

5.1 Quintal harmony (fifth-based)

Quintal harmony is the complement of quartal harmony, building chords by stacking perfect fifths (e.g., C–G–D–A–E). Its sound is similar but slightly more open due to the larger interval. Composers like John Foulds and Leoš Janáček used quintal chords occasionally.

5.2 Secundal harmony (second-based)

Secundal harmony stacks major or minor seconds (e.g., C–D–E♭). This produces dense, cluster-like sonorities, often associated with dissonant modernism. While less common than quartal harmony, it appears in works by Charles Ives, Henry Cowell, and Béla Bartók.

5.3 Terminological distinctions

Some theorists distinguish “quartal harmony” (chords built only on perfect fourths) from “quartal-quintal harmony” (including both fourths and fifths) and “pandiatonic quartal harmony” (using diatonic fourths within a key). In jazz pedagogy, the term “fourth voicing” is often used to describe any chord that contains at least two fourths.