Cassette tapes are the favored medium of the noise underground, a subculture that has had more and more to do with techno as of late. Apart from their nostalgic aspects, their clumsy tactility and muddy, mid-fi sonics create an atmosphere that Ruaridh Law exploited to maximum effect under his TVO alias on last year’s creeping Red Night. Formally comparable to Echospace’s similarly epic and at times inhuman The Coldest Season, beats arise only reluctantly out of vast pools of primordial, static-laden drone. Climaxing with an extended passage of William S. Burroughs reading from the namesake novel Cities of the Red Night, its cumulative effect eclipsed any single track—it was a Möbius strip of plague-addled ambient techno, the contents custom made for what the medium has become in the digital-music era. Law’s Broken60 label is following up that considerable statement with a two-sided epilogue, pairing further tracks from TVO with reinterpretations of four Red Night tracks by Covered in Sand. Best known for last year’s stark and ambience-choked album as Shifted, Crossed Paths, Guy Brewer dives deeper into the earlier album’s murky depths, while TVO evolves his earlier work into five rhythm-oriented cuts.

The TVO tracks that open the collection are designed to be free standing, and they initially light on a vibe that might seem very different from the sprawling and often beatless Red Night. But not too far underneath the more aggressive surface, Law is working with similar ideas. A backwards, disembodied liturgy haunts “Outside the Brighton Church,” like Current 93 in its early, avant-garde phase gradually smothered by switching, interlocking drums and a toxic drone. Once the major pieces lock into place, TVO lets entropy take over. A dense fog of reverb drifts through a scampering battery of percussion on “Concrete and Steel, Peckham,” an edifice that builds on itself steadily until it disappears into the clouds above.

The actual Variations lie in the second half of the album. Covered in Sand’s interpretations are on average shorter than TVO’s first five tracks, but feel distinctly longer and more static. This malaise isn’t surprising given the severe minimalism of Crossed Paths, but these prickly meditations don’t quite gel with what came before. Taking Red Night‘s most hollowed-out moments as a starting point, Covered in Sand proceeds to do what his name promises, interring the original album under a fine layer of silt and the cold bite of tunnelling reverb. His treatment of “Ba’dan” is his most well-rounded contribution, developing a sickly tension between a freakishly changeless hi-hat pattern and a bristling held tone that may have issued from a technically interesting iPad app. “Yass Waddah” and “Many Lifetimes” pass more or less unnoticed, but the album is rounded out by the incredibly tough bass-drum barrage of “Naufana,” whose industrial intensity evokes and outdoes Vatican Shadow. Meanwhile, a Hieronymous Bosch panorama of wailing souls howls in trapped agony, caught with unnerving beauty in the amber of Covered in Sand’s sampler.