Gran Torso, for string quartet, was composed in 1971 and revised in 1978. It belongs to a series of works, including Air, Kontrakadenz, Pression and Klangschatten, whose concept of material attempts to free itself from convention. That is, instead of using the sound itself as a point of departure, structural and formal hierarchies are derived from the mechanical and physical conditions present during the process of sound production. It is clear that such a radical break with tradition is not easily achieved: the instrument, the given means, the resonating body itself (as the embodiment of convention) all work against such attempts (with the extended performance techniques representing only the tip of the iceberg of deep-seated contradictions where the bourgeois artist is concerned). Implicit in such a challenge, however, is a claim to aesthetic pregnance: an offer, if one would have it, of uncomprosing beauty.
(Helmut Lachenmann, 1978)