In the two-movement Cello Concerto (1966), Ligeti continued to develop his personal notion of musical gesture as an almost linguistic or semantic unit, which he had previously explored in the vocal/ensemble works Aventures (1962) and Nouvelles aventures (1962 – 65). The cello begins the work on a single pitch at a virutally inaudible pppppppp dynamic. From this focal point the first movement intensifies, expanding into dense, amorphous textures reminiscent of the glacially changing sonic clusters of works such as Atmosphères (1961). This process of growth continues throughout most of the movement, which ends with a high cello harmonic and a low bass note bounding a gulf of emptiness.
The expressively kinetic second movement begins with the presentation and apparent rejection of several ideas that ultimately return in new contexts. The solo cello remains at the fore, though the orchestra likewise teems with activity. Complex polyphony and mechanistic polyrhythms dominate the texture; the overall impression is one of limitless possibility, in which anything can happen, including musical events that have already taken place. The movement ends with frantic ponticello scraping that fades into the nothingness that began the concerto.
The fifteen-minute Cello Concerto was premiered in Berlin on April 19, 1967. The orchestra calls for flute, oboe, two clarinets, horn, trumpet, trombone, and a small string section.
– Robert Kirzinger