American Band’s Low Fiction and Jeff Rehnlund’s Gangnam Basement comprise the first two vinyl albums for Hot Releases, the new tape/ zine/ CD-R/ LP label from Triangle noise boys Rehnlund and Ryan Martin, both of Boyzone. But these LPs are united by more than mere convenience of imprint: Both represent significant advances for those that made them, especially in each act’s improved ability to sculpt surprising sound sourcesa piece of sheet metal or the streets of South Koreainto layered music as capable of being violent as it is vulnerable.

American Band’s debut, 2007’s cannily titled American Band’s First Album, was a five-track pulverization, an all-or-nothing assault: Lee Counts, a Triad painter, pushed his power tools against sheets of scrap metal, while Jason Crumer (of Facedowninshit and his own solo noise glory) and Matt Franco (Air Conditioning) lifted that sound with roaring power electronics. “General’s Lament,” the album’s only curtsy to quiet and one of the best noise tracks of this decade, opened with an organ drone before exploding into shards of mechanics and manipulations. By track’s end, American Band seemed intent upon destroying all speakers and senses.

But Low Fiction opens softly, an automatic hum disrupted by clicks and crackles, like a microphone being wiped with tin foil in a computer lab. It fades to near-quiet, a sigh laced with sinister overtones that build into the temperate “Had Only.” The track is a haunting moan, suggesting the sound of a French horn played underwater. It’s all a tease for “Everyone Knows the Way,” the colossal track that closes Side One. A coruscated catastrophe, “Everyone” stops just short of overpowering, showcasing an American Band that’s more patient and controlled, building a big sound only to let it spin off and, soon enough, die away.

Let’s not romanticize too much: Side Two is American Band at its most destructive, electronics and metal-on-metal sparks flying through the speakers as soon as stylus touches wax. Throughout the side, though, the trio reveals new hands, including an expanded tonal palette that breaks beyond the mid-range bludgeon of earlier American Band. Passes of feedback and reverse signals send shivers up spines, something that American Bandfor so long, more force than finessehas avoided. Low Fiction represents the next essential step for this fascinating trio and one of the decade’s best trips through North Carolina noise.

Meanwhile, Rehnlund recorded Gangnam Basement during 2006 and 2007 while living in Seoul, South Korea. Gangnam is a densely populated district of Seoul that Rehnlund calls “expansive, tall, rich, sexy, fake.” Like his earlier solo releases on Florida label Hymns and venerable New England noise syndicate RRRecords, Gangnam Basement employs field recordingsmuffled, messy moments captured with a handheld recorderas a starting point for tape manipulation. Like those previous Rehnlund records, Gangnam captures a wide-eyed sense of wonder, showcasing a young, curious sort who explores his new environment with great zeal. He listens and documents, then refracts his experiences through his own artistic lens. A third party peering out of Rehnlund’s pocket, we hear the joys and anxieties of his discovery and disappointment. Here, Rehnlund wraps the chatter of children, the voice of a loquacious man, and the tunes of a Korean classical ensemble into two 20-minute, six-track sides.

Gangnam is Rehnlund’s most ambitious and accomplished compositional music to date, though, importantly going a step beyond his past by not simply cutting from one sample to another or bending them through analogue distortion. The field recordings become biological backdrops and teeming sound sources. Instead of a dated itinerary or travelogue, Rehnlund turns them into impressions and reflections. His feelings about his surroundingsthe visceral terror that spins into “Tiger Tongue,” the hypnotic loop of Korean voices on “Yondo,” the halcyon bass modulations and gentle trebly whirs of “Inwangsan”are implicit, not explicit. The sounds are richer, more dynamic and varied, with greater breadth of tone and texture. Moments are brittle and beautiful, andat Rehnlund’s besthe finds space for both at once.

While that sonic evolution may cost Rehnlund’s work some of its previous idiosyncratic distinction (see 2007’s “Raleigh”), it should ultimately give him more room to explore beyond simple scramble-the-tape collages. That is, Rehnlund’s no longer just our tour guide. He’s our trip’s essayist and interpreter, too.