In music, a tone row or note row (German: Reihe or Tonreihe), also series or set, is a non-repetitive ordering of a set of pitch-classes, typically of the twelve notes in musical set theory of the chromatic scale, though both larger and smaller sets are sometimes found.
Tone rows are the basis of Arnold Schoenberg's twelve-tone technique and most types of serial music. Tone rows were widely used in 20th-century contemporary music, e.g. Dmitri Shostakovich's use of twelve-tone rows, "without dodecaphonic transformations", though one has been identified in the A minor prelude from book II of The Well-Tempered Clavier (1742) by J. S. Bach, and by the late eighteenth century was a well-established technique, found in works such as Mozart's C major String Quartet, K. 157 (1772), String Quartet in E-flat major, K. 428, String Quintet in G minor, K. 516 (1790), and the Symphony in G minor, K. 550 (1788).Beethoven also used the technique but, on the whole, "Mozart seems to have employed serial technique far more often than Beethoven".Hans Keller claims that Schoenberg was aware of this serial practice in the classical period, and that "Schoenberg repressed his knowledge of classical serialism because it would have injured his narcissism."
Tone rows are designated by letters and subscript numbers (e.g.: RI11, which may also appear as RI11 or RI-11). The numbers indicate the initial (P or I) or final (R or RI) pitch-class number of the given row form, most often with c=0. P indicates prime, a forward-directed right-side up form. I indicates inversion, a forward-directed upside-down form. R indicates retrograde, a backwards right-side up form. RI indicates retrograde-inversion, a backwards upside-down form. Transposition is indicated by a T number, for example P8 is a T(4) transposition of P4.
A twelve-tone composition will take one or more tone rows, called the "prime form", as its basis plus their transformations (inversion, retrograde, retrograde inversion, as well as transposition; see twelve-tone technique for details). These forms may be used to construct a melody in a straightforward manner as in Schoenberg's Op. 25 Minuet Trio, where P-0 is used to construct the opening melody and later varied through transposition, as P-6, and also in articulation and dynamics. It is then varied again through inversion, untransposed, taking form I-0. However, rows may be combined to produce melodies or harmonies in more complicated ways, such as taking successive or multiple pitches of a melody from two different row forms, as described at twelve-tone technique.
Initially, Schoenberg required the avoidance of suggestions of tonality--such as the use of consecutive imperfect consonances (thirds or sixths)--when constructing tone rows, reserving such use for the time when the dissonance is completely emancipated. Alban Berg, however, sometimes incorporated tonal elements into his twelve-tone works, and the main tone row of his Violin Concerto hints at this tonality:
This tone row consists of alternating minor and major triads starting on the open strings of the violin, followed by a portion of an ascending whole tone scale. This whole tone scale reappears in the second movement when the chorale "Es ist genug" (It is enough) from Johann Sebastian Bach's cantata O Ewigkeit, du Donnerwort, BWV 60, which opens with consecutive whole tones based on Johann Rudolf Ahle's melody from 1662, is quoted literally in the woodwinds (mostly clarinet).
B, B♭, D, E♭, G, F♯, G♯, E, F, C, C♯, A
If the first three notes are regarded as the "original" cell, then the next three are its retrograde inversion (backwards and upside down), the next three are retrograde (backwards), and the last three are its inversion (upside down). A row created in this manner, through variants of a trichord or tetrachord called the generator, is called a derived row. The tone rows of many of Webern's other late works are similarly intricate.
The "set-complex" is the forty-eight forms of the set generated by stating each "aspect" or transformation on each pitch class.
The all-interval twelve-tone row is a tone row arranged so that it contains one instance of each interval within the octave, 0 through 11.
A "secondary set" is a tone row which is derived from or, "results from the reversed coupling of hexachords", when a given row form is immediately repeated. For example, the row form consisting of two hexachords:
0 1 2 3 4 5 / 6 7 8 9 t e
when repeated immediately results in the following succession of two aggregates, in the middle of which is a new and complete aggregate beginning with the second hexachord:
0 1 2 3 4 5 / 6 7 8 9 t e / 0 1 2 3 4 5 / 6 7 8 9 t e secondary set: [6 7 8 9 t e / 0 1 2 3 4 5]
A "weighted aggregate" is an aggregate in which the twelfth pitch does not appear until at least one pitch has appeared at least twice, supplied by segments of different set forms. It seems to have been first used in Milton Babbitt's String Quartet No. 4. An aggregate may be vertically or horizontally weighted. An "all-partition array" is created by combining a collection of hexachordally combinatorial arrays.
Schoenberg specified many strict rules and desirable guidelines for the construction of tone rows such as number of notes and intervals to avoid. Tone rows that depart from these guidelines include the above tone row from Berg's Violin Concerto which contains triads and tonal emphasis, and the tone row below from Luciano Berio's Nones which contains a repeated note making it a 'thirteen-tone row':
Igor Stravinsky used a five-tone row, chromatically filling out the space of a major third centered tonally on C (C-E), in one of his early serial compositions, In memoriam Dylan Thomas.
Ben Johnston uses a "just tone row" (see just intonation) in works including String Quartets Nos. 6 and 7. Each permutation contains a just chromatic scale, however, transformations (transposition and inversion) produce pitches outside of the primary row form, as already occurs in the inversion of P0. The pitches of each hexachord are drawn from different otonality or utonality on A+ utonality, C otonality and utonality, and E♭- otonality, outlining a diminished triad.
A literary parallel of the tone row is found in Georges Perec's poems which use each of a particular set of letters only once.
"Tone row" may also be used to describe other musical collections or scales, such as in Arabic music.