The paths of saxophonist Mats Gustafsson, guitarist David Grubbs and trumpeter Rob Mazurek have crossed and crossed again since they were all active on the Chicago improvised music scene in the 1990s. By now, they're all big-hitters with voluminous back catalogues and serious reputations – so it's gratifying to hear them leaving their baggage behind and making time to stretch into unknown territory. Recorded on tour in Europe, their second album as The Underflow picks up where their 2019 self-titled debut left off, mixing acoustic instruments with live electronics to build very neatly delineated sound sculptures. The title track layers bobbing, percussive sax with bubbling effects and time-lag horn echoes, suggesting one of Terry Riley and Don Cherry's mid-1970s jams. ‘Self-Portrait as Interference Pattern' begins with the kind of early-noughties harsh noise puke that Gustafsson still enjoys, seeded with Mazurek's echo-delay cornet tracers nodding towards his previous collaborations with mentor Bill Dixon. Throw in three spontaneous arrangements of songs previously recorded by Grubbs and there's a lot of ground covered in 90 action-packed minutes.