Dave Rempis / Joshua Abrams / Avreeayl Ra / Jim Baker: Apsis

After appearing on one half of Perihelion (Aerophonic, 2016), keyboardist Jim Baker has joined Chicago saxophonist Dave Rempis' working trio with bassist Joshua Abrams and drummer Avreeayl Ra on a permanent basis. In one respect the band seems one of the most traditional of the reedman's projects.

That's largely down to how the instruments in the main stick to their allotted roles and tonalities in two slabs (25 and 35 minutes plus) of unapologetic make-it-up-as-you-go rhythmically inflected free jazz. But while they don't seek to exploit extended techniques, how they interrelate is far from conventional, especially when Baker switches from the piano to synthesizer.

Each cut unhurriedly evolves, taking in group and solo sections, touching on a panoply of styles and feels. Ra demarcates an intuitive current, shifting in and out of time with splashy cymbals and chattering drums which channel Art Blakey and Ed Blackwell via Sunny Murray. On bass, Abrams imparts momentum through a series of non-repeating but rhythmic figures or an anchoring pulse. And both are comfortable slipping into relaxed grooves. No surprise given Abrams' leadership of the trance-inclined Natural Information Society.

Rempis positions himself as part of the team right from the start, launching a steady four way churn on baritone saxophone at the beginning of "Exedra." There's a strong connection evident between him and Ra, manifest later when the drummer accents the hornman's unfettered alto torrent with a conversational chatter. As a pianist, Baker proves equally responsive, providing blocky accompaniment with a percussive approach, which compliments as much as it cajoles.

But the change to electronics on "Mithrab" is more provocative, alluding to everything from Sun Ra at the organ to industrial noise. When at the outset his synthesized wail intertwines with Rempis frothing tenor the effect is electrifying, while a subsequent leaping staccato exchange with the saxophonist constitutes one of the disc's highlights. However it's not all milk and honey as matters turn edgy and unsettling when he cuts across the flow, going against the grain, though it's a move that might just be the grit needed to form the pearls.