(Sean Brackbill/Motormouth Media)

For second album “Nootropics,” the group has taken its arrangements and stretched everything out, creating a minimalist Krautrock vibe that features added synthesizers and a mood that is much more sparse and murky.

The trick in such an undertaking is to not stretch too far, to the point where holes start to form and, eventually, everything pulls apart. On this count, Lower Dens has succeeded in creating an album that requires your patience but is also worthy of it.

The first single, “Brains,” slowly deploys machinelike percussion; long, dense synthesizer tones; lead singer Jana Hunter’s vocals; and layers of guitars to build an enthralling psychedelic swirl. “Propagation” takes a divergent path, surrounding vocal harmonies with a steady backing beat of drums and bass and minimalist guitar touches.

The payoffs don’t normally come in big hooks, but in the way tones meld and are twisted and bent; the small parts work slowly in concert to create a unique whole. “Nootropics” might not catch on immediately with those who appreciated the crispness of “Twin-Hand Movement,” but it certainly merits deeper exploration.

With Violens on Friday at the Rock & Roll Hotel. Show starts at 8 p.m. 202-388-7625. www.rockandrollhoteldc.com. $10.