Sofia Gubaidulina’s Duo Sonata composed in 1977 was originally scored for two Bassoons, but has become very popular among saxophonists. Gubaidulina deftly weaves the parts together in a flowing form with cadenzas and a ritornello, taking advantage of the near-identical timbres and richness throughout the instruments’ range to create moments of ambiguity and lucidity over the course of the work. The activity is distributed very equally between the parts, each sharing melodic and supporting roles, and taking part in a foray of contemporary and extended techniques, including flutter-tongue and growling, altissimo, accelerando figures and challenging articulation patterns, and most notably, multiphonics and quarter-tones. Indeed, the work is primarily concerned with the last of these, the second part unfolding above a gradual quarter-tone ascent over more than two octaves. Most of the extended techniques for bassoon cross over quite naturally to saxophone, with only slight modifications or substitutions necessary on a limited basis. The multiphonics have been selected to reflect the original bassoon pitch content as closely as possible, while also retaining the intended voice-leading. - Michael Couper