At the end or 2019, German virtuoso pianist/composer Michael Wollny invited three former playing partners – American bass guitar star Tim Lefebvre, ingenious French soprano saxophonist Emile Parisien, and German free-jazz drums whirlwind Christian Lillinger – to join him at Berlin's A-Trane club for four nights of unpremeditated free-jamming. Two months later in Atlanta, Wollny and Lefebvre co-edited and sonically enhanced eight hours' improv to less than one at the studio of the bassist's producer friend Jason Kingsland, and the remarkable XXXX is the outcome.

The undertows are often fiercely, abstractly and sometimes caressingly electronic (Wollny plays electric keys throughout), from the chain-dragging sounds and detonations of ‘Somewhere Around Barstow’, to the choirlike echoes and huge, chugging grooves of ‘Too Bright In Here’ or the dreamy harmonies of the only composed piece, Wollny's closing ‘Nostalgia for the Light’. But, though there may be a shade too little discernibly jazzy improv for some, the music fizzes with melodic and rhythmic surprises – notably from Parisien, whose twisting and unimpededly acoustic lines against Lillinger's dazzling polyrhythms on ‘Dick Laurent Is Dead’ and wistful spaciousness on ‘Michael vs Michael’ are highlights, as is Wollny's own devious agility on the latter, and his churning grooves and old-school synth twangs on ‘The Haul'. A double-album rather than such a mercilessly tight edit might have represented the participants’ individual as well as collective contributions more fairly on this fearlessly action-packed experiment – but the participants want to tour it live, and it will be a fascinating experience when they do.