Forging ahead from their inaugural collaboration with minimalist electronica master Jan Jelinek and the loop-based experimentation of their "solo" debut Moment Returns, the Australian group Triosk continue to wander and explore in a hazy territory that's probably best described as post-jazz. At times, they flirt with the semblance of a relatively straight-ahead modern piano jazz outfit -- opener "Visions IV" in particular evokes the muscularity of the Bad Plus, with only a couple of minor electronic flourishes. More often they sacrifice nearly all of the fundamentals of jazz (and, for that matter, most music) -- melody, all but the most basic chordal harmony, in some cases all but the vague suggestion of rhythm -- in the single-minded pursuit of texture. It's this conceptual minimalism, the absence of jazz-like forms and structures, more than the actual sound of the album, that nudges The Headlight Serenade from jazz toward the ambient/electronic category. After all, it is still predicated on improvisation, and the bulk of it consists simply of piano, bass, and drums, readily recognizable as such even when electronically tweaked. Indeed, some of these tracks gives the impression of two jazz groups playing at once: one set of musicians holding down a slow-burning, melancholy jazz vibe (a brooding waltz on "Not to Hurt You," pensive chordal meditations on "One, Twenty-Four") while another sends twitchy, rhythmically unhinged fluctuations (warped metallic clangs, scraped and plucked piano strings, willfully erratic improvising from drummer Laurenz Pike) skittering across the surface. Triosk employ this basic formula -- a calm, largely organic undercurrent juxtaposed with turbulent, often spasmodic sound splashes -- in myriad ways and to great effect throughout the album. "Intensives Leben" sets hypnotically chiming, washed-out piano tremolos and periodic bass throbs beneath a steadily churning mechanical stream of scrap-metal clicks and clinks; the placid pedal-point gloss of "Lost Broadcast" subtly builds in intensity as spectral sounds waft in and out; "Headlights" sneaks slowly and slinkily through a minefield of eerie burbles, percussive crashes, and what sounds like a banjo. It's abstract and potentially very heady material, but Triosk cultivate a simple, fleet-footed grace and an impressive depth of emotion that allow the album, as the group no doubt intended, to slip easily into the background without diminishing its evocative potency. That is, at least until the final cut, "Fear Survivor," which lets loose a manic drum solo, unspooling with formless, electronic-mauled abandon, before giving way to a simple, plaintive piano ostinato. A successful venture on numerous levels, The Headlight Serenade is nearly as forward-thinking as it is listenable.