Now it has been scientifically proved that chaos keeps the world rational, anybody inhabiting that world, who is sensitive to its vibrations, can only embrace Iannis Xenakis as one of their own. These three pieces – Linaia-Agon (trombone, horn and tuba, 1972), Eonta (piano, two trumpets and three trombones, 1963) and Gmeeoorh (1974), Xenakis’s solo organ classic – were recorded live at Amsterdam’s Orgelpark in 2011. The stated aim of the Orgelpark is to hunt down a fresh identity for organ music, and organ repertoire doesn’t come much fresher than Gmeeoorh, his systematic deconstruction and re-engineering of the instrument.

By thinking the organ into being an empiric source of sound, Xenakis questioned every cliché about its churchy associations. Jan Hage’s performance, startlingly close-miked, is excellent. Gmeeoorh opens with chromatic slithers that in lieu of Xenakis’s trademark glissandos – no can do on an organ – float sound through space: motifs inch forwards, slip backwards and flip to either side with the inscrutable logic of chess. When, for no apparent reason, the music drops down a black hole, it gradually re-emerges from the stillness as points on a jagged curve towards strategically placed climactic clusters. As a drone of consonant harmony drifts towards the surface, Hage simply lets the moment be, then moves on. An exploded diagram of a split-second fission stretched over 18 minutes: that’s what Gmeeoorh does.

Hage’s performance is deliberate and spacious, not words that could be convincingly applied to Eonta. A pianist friend – who has performed Eonta – tells me that Xenakis’s piano-writing is highly idealistic (nice euphemism, that). Only a mug would second-guess how precisely Nora Mulder nails Xenakis’s notes, but this music isn’t about target practice. The pianist symbolises water and the brass represent light refracting through the gaze of the sun. I’m reminded of a David Hockney splash as Mulder’s physical, alert pianism spills out against the streamlined frame provided by the brass. Linaia-Agon is, I’d say, second-tier Xenakis; no doubting this performance’s boorish splendour though.