Every sound on this record comes out of a bassoon. Eric Wubbels, the New York composer and pianist, wrote Altarpiece H. af K. for three bassoons in 2021 and revised it in 2025: multiphonics played in tripled unison that throw off clouds of combination tones, dissonances that beat so heavily they make the floor shake, whistle tones pushed to the very top of the instrument's range. A 'sculpture of air pressure', in his words, somewhere between the spectral worlds of Scelsi, Radigue and Dumitrescu and the physical weight of Sunn O))).

The piece began at the Guggenheim in 2018, at the exhibition Hilma af Klint: Paintings for the Future, in front of the three Altarpieces of 1915, stacked pyramids of colour climbing towards and falling away from a golden sphere. Following the old form of the canon, one voice starts and the others follow, the music moves from thick masses of vibrating air to ricocheting drones and fragments of melody, sinks into darkness and rises to a bright consonance before ending in disembodied harmonics.

Played by Dana Jessen, Ben Roidl-Ward and Katherine Young, who workshopped and toured the piece for years, and recorded by Randall Dunn at Power Station in New York in December 2025. The insert reproduces the graphic score with Wubbels's notes. Released by Kou Records.