When he was admitted to a psychiatric hospital, the composer Giacinto Scelsi nursed himself back to health by playing a single note over and over on the piano, entering meditatively into its sound. The beginning of Sarah Hennies’s delicate Unsettle for piano and percussion recalls this. Bent Duo languidly guide us through successive spare environments of sound, many of them based on single repeated piano notes accompanied by unpitched percussion or electronic oscillation. From a two-page score emerges half an hour of music: minimal means, maximal exploration.

As Hennies notes, listening to a single repeated event for five minutes has the effect of altering your perception. The event somehow transforms while remaining the same. It feels as if Hennies is going back to minimalism’s roots in austere experimental processes, before it was channelled into a new tonalism. Unsettle at times features vibraphone to generate rich overtones by repeated notes and chromatic dyads.

Spectral Malsconcities for trio, the other work here, is also half an hour long and slightly less reductive. Hennies has said that the score, much of which is metrically asynchronous (each performer playing in a different metre), was conceived this way so that the performance would fall apart after a while. As it turned out, the virtuoso ensemble were able to play it perfectly; this gave a better result than she had imagined. Bearthoven’s virtuosity is understated and their sound (piano, double bass, percussion) recalls a free-improvisation group. The second of the Spectral Malsconcities’ five sections sees polymetrical notes pulsating ad nauseum. The trio’s repeated motifs and pulses create a steady auditory frame of reference Hennies exploits by throwing in irregularities and parasitic elements.

In both works, the grain of the instrumental sound is audible: squeak of percussion, scratch of materials. This alerts us to the living quality of the music: the performers, their heartbeats; the bodily energy making the sound happen, the thoughts running through the performers’ minds. Hennies was recently the subject of a New York Times article and this disc captures her at an interesting early career stage.