Jakub Alexander’s most recent album under his Heathered Pearls alias, last November’s Cast, is a collaborative affair with an unusual twist. Feeling that something was missing from his instrumental tracks, the Brooklyn electronic musician invited friends and peers to contribute spoken-word recordings to be woven into his own productions. Embedded deeply into the mix, these muttered ruminations lend human warmth even when the words remain indistinct. “Salvaged Copper” is one of the album’s deepest, most enveloping tracks, and also one of its subtlest. Over beatless waves of reverberant synths, Detroit’s Terrence Dixon speaks just once, briefly: “Every time I step outside, people face change; no smiles.”

Despite its three-minute length, “Salvaged Copper” feels almost like an interlude, no more substantial than a mirage: just shimmering chords and Dixon’s fleeting observation. But a remix by the UK producer Luke Slater draws it out into a 17-minute epic. The remix begins almost exactly like the original, held aloft on the same drowsy synthesizer loop. But as it stretches out, it grows in proportion, swelling with additional drums, synths, and effects. In the early 1990s, under his 7th Plain alias, Slater was responsible for some of ambient techno’s most transporting productions, and he revisits that style here. Thick with contrapuntal layers, tossed this way and that by colliding waves of sound, Slater’s remix is a powerful fusion of Detroit techno’s futurist yearning and classical minimalism’s hypnotic focus. Every now and then, Dixon’s voice cuts through the swirl. While everything else is lifted skyward, he remains a grounding presence.