Composing with Twelve Tones

In twelve-tone composition, the row governs pitch-class order but leaves virtually all other parameters — rhythm, dynamics, register, articulation, texture, form — to the composer's discretion. The row may be stated melodically (one note at a time), harmonically (as chords, with adjacent row members sounding simultaneously), or in any combination. Pitches belonging to the current row form can be repeated or sustained before the next pc in the series is introduced; however, the order of pitch classes must be maintained.

Selecting which row form to use at any given moment is a compositional decision. Many composers move from one row form to another at phrase boundaries, at formal divisions, or when passing from one instrument to another. A common strategy is to pair two row forms whose hexachords complement each other (combinatorial pairs), so that each voice presents six pitch classes and the two voices together form a complete aggregate. This allows harmonic control at the surface without breaking the twelve-tone ordering within either voice.

Row segmentation — grouping the twelve pitch classes into subsets called segments, trichords, tetrachords, or hexachords — is another essential compositional technique. A composer may consistently present the row in four groups of three (trichordal segmentation), making the motivic units of the row into building blocks for melody and harmony alike. Webern's music is especially rich in this technique. Finally, the row can be partitioned across instruments in an ensemble so that no single part states the complete row, but the full series is present in the collective texture — a technique that allows twelve-tone logic to coexist with transparent counterpoint.