Lumsdaine was much affected by the later works of Anton Webern, though his music sounds very different from the many other composers of the fifties and sixties who were interested in this composer. Webern's use of symmetrical harmonic fields to focus and control the vertical functioning of his polyphony was a crucial stimulus. Lumsdaine's own harmonic language has elements of symmetry and intervallic limitation, and though usually derived from 12-pitch sets, is rarely strictly chromatic. In his masterly piano work 'Kelly Ground' (1966) the harmonic ground is a characteristic chordal area which, although dissonant overall, contains numerous quasi-diatonic subsets, with the interval of perfect fourth especially prominent. The overall progression of the work is towards the elimination of all extraneous pitch elements until only the ground itself remains.