Ole-Henrik Moe, a Norwegian composer of works for solo violin that are expertly performed by his wife, Kari Ronnekleiv, offers two substantial pieces here on a two-disc set released on the Rune Grammofon label. Though they’re separated by seven years in the date of their composition, “Ciaccona” and “3 Persephone Perceptions” are clearly the work of the same composer: squeals of tremolo harmonics, repeated sawing noises, and prolonged periods of silence (or below-the-limit-of-hearing figures) are hallmarks of Moe’s compositional style. This is challenging stuff.

Harmonics are key to both of these compositions. Especially on “3 Persephone Perceptions”, which exists for most of its 40-minute length in a space where clashing harmonic notes are underscored by scratches of rosin-friction noise. The purported idea is to explore the ‘inner components’ of the instrument’s harmonics: in the process, the traditional bowed sound you think of when you imagine a violin has been deconstructed so much as to be unrecognisable. On “Ciaccona”, too, the aim of unlocking new sonic landscapes is an obvious one. On the borders of silence, diminutive harmonics echo in calm dissonance (until the final movement).

It’s a complete mystery how Ronnekleiv produces these sounds. From the flurried tremolo chords to glissandi and ghost jitters, it sounds as if either the sound’s been expertly manipulated by computer, or (more likely) as if the bow has been played reversed, with the wood scraping against the strings. Certainly it’s likely that there are passages in which the strings above the bridge are scratched—the dramatically shorter length means there are no real notes, up there, only harmonic scratches. Simultaneously high/low, layered/simple, Moe’s compositions evoke complex paradoxes not only metaphorically, but in the sound itself.

Both pieces make the most of contrast. Vicious attacks of noise ebb and flow with periods of absolute silence—the kind that makes you strain to hear what’s going on, if there’s any sound at all. Between the eighth and ninth sections of “Ciaccona”, and between the second and third sections of “3 Persephone Perceptions”, a straightforward, bowed note brings a major jolt. In the latter, especially, the calmer ending section approaches conventional beauty: the first major seventh chord is gradually deconstructed entirely over the course of six and a half minutes, becoming a series of hesitations into the same thematic territory, but somehow becoming deeper, and more memorable, in the process.

The centrepiece of both albums is the 23-minute second movement of “3 Persephone Perceptions”. Hints of melody—or at least snatched moments of something that sounds like a recognizable note—are allowed to pop out of the texture. But they’re swallowed up immediately in the tremolo harmonic jitter. It’s unnerving and uncompromising, and only shifts minutely through the course of the movement.

The liner notes to Ciaccone/3 Persephone Perceptions quote an apparently influential sentence from Heraclitus: “A hidden structure is stronger than a visible one.” It’s certainly the case, for both “Ciaccona” and “3 Persephone Perceptions”, that the structure is buried deep in these spare, ascetic composition. If you’re feeling adventurous, see if you can dig it out for yourself.