Duo was originally written for violin and piano, but Sweeney intentionally left the instrumentation of the solo part open because he felt that the piece was more "a rhythmic working-out of certain motivic ideas rather than the expression of a particular instrumental timbre". Written in ternary form, Duo is essentially a lively and exuberant exploration of the tonal relationships of a three-note cell, F#-A-B, within various keys and using ostinato and syncopated rhythmic techniques.
Eric Sweeney studied at Trinity College Dublin and the Conservatorio di Santa Cecilia in Rome and is now Head of Music at Waterford Regional Technical College, Ireland. His musical language underwent a radical change in the late 1980s, abandoning his earlier style of extended tonality and free serialism and developing a personal form of minimalism by integrating elements of Irish traditional music. This stylistic shift in his compositional evolution was marked by two major works: Dance Music (1989) commissioned by the Royal Philharmonic Orchestra, and the cantata Diedre (1989).