Twentieth-Century Techniques
Twentieth-century composers expanded harmony beyond major-minor function. Quartal chords, planing, polytonality, pitch-class sets and twelve-tone rows organize sound through interval, register, symmetry and repetition instead of required V-I resolution.
- several systems, not one style
- interval can replace function
- context creates coherence
What changed after tonal harmony?
Tonal music did not disappear. Composers added systems that could weaken, suspend or replace tonic-dominant direction.
The term covers many approaches. Quartal harmony and polytonality can retain recognizable centers; atonality and twelve-tone technique may avoid a governing tonic.
What is quartal harmony?
Quartal chords stack fourths instead of thirds. C-F-B flat uses two perfect fourths and does not state major or minor quality in the way C-E-G does.
The bass and surrounding music can still create a center. Quartal voicings are common in jazz, film music and modal writing.
What is planing?
Planing moves one chord shape in parallel. Exact planing preserves every interval and introduces chromatic notes. Diatonic planing adjusts pitches to remain inside a scale.
The shared shape and direction provide continuity. Parallel fifths become the intended texture rather than an error against independent voice leading.
How do polytonality and polychords differ?
Polychord describes two recognizable chord structures heard together, such as D major over C major.
Polytonality describes simultaneous layers that support different key centers. It requires enough melodic and harmonic context for both centers to remain audible.
A complex stack is not automatically polytonal. Analyze how each layer behaves over time.
What is twelve-tone technique?
A twelve-tone row orders all twelve pitch classes before systematic repetition. The row can appear as original form, transposition, inversion, retrograde and retrograde inversion.
The method controls pitch recurrence; it does not determine rhythm, register, articulation or form. Different composers can produce very different music from the same procedure.
What creates coherence without V-I?
| Resource | What the listener can follow |
|---|---|
| Motive | recurring rhythm or interval shape |
| Pitch center | emphasis through register, duration or repetition |
| Symmetry | repeated interval cells or balanced collections |
| Timbre | stable instrumental color or spectral change |
| Form | return, contrast and accumulation across sections |
Atonal does not mean random. The organizing relationships simply need not be tonic, predominant and dominant.
How should you listen and experiment?
- Compare structuresplay C-E-G, then C-F-B flat.
- Move the quartal shapetranspose it in parallel by whole step.
- Layer two triadskeep register clear enough to hear both structures.
- Build a short rowuse all twelve pitch classes and repeat its first three-note motive rhythmically.
Keep going
Everything in harmony
- Four-Part Chorale Style
- Species Counterpoint
- Imitation, Canon and Fugue
- Counterpoint in Pop
- Jazz Harmony
- Twentieth-Century Techniques