With this pair of challenging, longform vocal works - including a recording of Kurt Schwitters’ Ur Sonate which has long been banned from being recorded by his estate - restless sound explorer John Duncan steers the vocal themes of his beguiling LP, This Bitter Earth, into the avant dimensions he’s best known for occupying since the late ‘70s.

Mantra is a 33 minute exposition of extended vocal technique where Duncan’s own vocals are layered and faded across the stereo field in an hypnotic, glacial escalation of density, calving away into a passage of fiercely tempestuous noise and back to the vocals. To be fair, it sounds nothing like the straight-played This Bitter Earth songs, but a transcendent appeal is mutual to both works.

We’re not entirely sure why the state of Schwitters banned recording of his classic, dadaist sound poem Ur Sonate, but Duncan either does/doesn’t give a fuck and so here it is in its psychotomimetic glory, 23 minutes of alien tongue joined by a 14 -part chorus, produced by Yelena Mitrjushkina for Narkissos Contemporary Art Gallery, Bologna, in Duncan’s adopted home city.