Wikipedia
Klangfarbenmelodie ( German for sound-color melody) is a musical technique that involves splitting a musical line or melody between several instruments, rather than assigning it to just one instrument (or set of instruments), thereby adding color ( timbre) and texture to the melodic line. The technique is sometimes compared to " pointillism", a neo-impressionist painting technique.
The term derives from Arnold Schoenberg's Harmonielehre, where he discusses the creation of "timbre structures." Schoenberg and Anton Webern are particularly noted for their use of the technique, Schoenberg most notably in the third of his Five Pieces for Orchestra (Op. 16), and Webern in his Op. 10 (likely a response to Schoenberg's Op. 16), his Concerto for Nine Instruments (Op. 24), the Op. 11 pieces for cello and piano, and his orchestration of the six-part ricercar from Bach's Musical Offering:
This may be compared with Bach's open score of the subject and the traditional homogeneous timbre used in arrangements:
Notable examples of such voice distribution that preceded the use of the term may be found in music of the 18th and 19th centuries. John Eliot Gardiner says of the orchestral opening of J.S. Bach’s Cantata Brich dem Hungrigen dein Brot, BWV 39, “Bach sets out almost tentatively in an introductory sinfonia with repeated quavers tossed from paired recorders to paired oboes to the strings and back over stiffly disjointed quavers in the continuo.”: In Beethoven's Symphony No. 3, (" Eroica"), first movement, according to George Grove, we hear "a succession of phrases of three notes, repeated by different instruments one after another": .
Similarly, in the fourth movement of Berlioz' Symphonie Fantastique ("March to the Scaffold"), the melody first appears as a descending scale played on 'cellos and basses: Later, this melodic line is passed between the strings and the winds several times: There are further instances in the works of Claude Debussy. Regarding the latter, Samson writes: "To a marked degree the music of Debussy elevates timbre to an unprecedented structural status; already in Prélude à l'après-midi d'un faune the color of flute and harp functions referentially."
In the 1950s, the concept inspired a number of European composers including Karlheinz Stockhausen to attempt systematization of timbre along serial lines, especially in electronic music.