As the Sheffield-based composer, improviser and jazz saxophonist Martin Archer explains, his new ‘Quartets’ series will showcase records rehearsed and recorded over a period of two days. For those of us versed in earlier Archer albums like Heritage and Ringtones and In Stereo Gravity, which were structured in the studio after collating material from different musicians over a number of months, this return to real-time improvisation presents an intriguing prospect and Archer doesn't disappoint. Sunshine! Quartet is the pick of the pair. The play off of tart, staccato saxophone against the ever-alert harmonic slipstream of Corey Mwamba's vibraphone inevitably invokes distant memories of Eric Dolphy's Out to Lunch! – as does the underlying structural tension between freedom and groove. Each member of the quartet contributes a composition and throughout the musicians don't just play the structures, but actively transform their composed beginnings through the process of improvisation; Mwamba's knack of reaching inside and gently spinning the material in a wholly unexpected direction is beguiling. At 75 minutes, Felicity's Ultimatum can feel rambling, but there is much to enjoy – including the soulful ‘Rachel's Walk (with Roscoe)’ and the title track, where Archer and Graham Clark become like a hybrid instrument melting into balletic sweeps from Johnny Hunter's kit in a spacious and disciplined free improvisation.