The Swedish quartet Dungen is one of the more schizophrenic rock acts on the scene these days. Over the course of its previous five albums, the band — primarily the outlet for singer/composer/multi-instrumentalist Gustav Ejstes — has constructed swirling paisleys of reverberative, fuzz-drenched psychedelic rock and soft, lilting melodies of foresting folk. And rarely do the two meet. On Dungen’s latest album, “4,” which is out today on Kemado Records, that Jekyll-and-Hyde split of musical personalities is at its most pronounced.

Luckily, Dungen can effectively play both styles with deft precision and emotive nuance, and the vacillation between extremes works best when it creates a taut dynamic. But on “4,” Mr. Ejstes has stitched together a baroque, beguilingly pastoral batch of folk tapestries — many of which are accented or powered by a keyboard, lending them a decidedly 1970s lounge vibe — at the expense of the band’s intoxicating explorations of noisy inner space.

Of the 10 tracks here, only two delve into Mr. Ejstes’s consummate gift for the run-on-sentence guitar workout. When Mr. Ejstes reaches for such beautiful overkill on “4,” the album swells with dizzying joy. “Samtidigt 1,” a three-minute eruption of Mr. Ejstes’s guitar acrobatics, finds him firing off bent-string squeals, power-chord throbs, and bluesy note progressions. That energy is reprised with a more meditative flair on the album’s penultimate track, “Samtidigt 2,” a four-and-a-half-minute journey through Mr. Ejstes’s more spaced-out, trance-inducing string work.

Both songs recall the type of guitar heroics pioneered by 1960s power trios such as Cream and the Jimi Hendrix Experience (both are clear influences), as well as the more exploratory work indulged, for one prominent example, by guitarist Manuel Göttsching and the early-’70s progressive rock band Ash Ra Tempel. Mr. Ejstes echoes not only the musicality but the soundscapes of the classic guitar era: His distortion is beefy and frayed around the edges on “Samtidigt 1,” and ringing and sustained on “Samtidigt 2.” Mr. Ejstes favors the crisp ripples and muscular warmth derived from playing through vintage tube amplifiers and non-digital effects pedals.

It’s a retro approach that many metal bands and audiophile producers swear by, but it doesn’t necessarily translate into a retro sound. And that’s what’s most disarming about Dungen at its fuzzy, noisy best: The foursome doesn’t sound like a band trying to re-re-create the music of the past. Rather, it sounds like a band using the tools and ideas of the past to make chaotic whorls that are perfect for getting lost in today.

When Mr. Ejstes goes pastoral on “4,” though, the ghosts of the past begin to haunt the music a bit too much, if only because the down-tempo moments are so polished. Album opener “Sätt Att Se” starts off well enough as an airy psychedelic ballad powered by a wash of strings drifting into screaming guitar notes and punctuated by a driving pulse. But it’s the rare example of such alchemy bringing engagingly woozy results.

Elsewhere, “4” sounds like Mr. Ejstes was aiming for easy-listening smooth jazz or, worse, the safer moments of Steely Dan in the late 1970s. What sounds like a lute makes “Mälerås Finest,” with its romantic strings and singsong piano melody, approach a parody of British folk. The piano and gentle hand-claps of “Ingenting Är Sig Likt” push the song along at a Ben Folds pace. And album closer “Bandhagen” begins with a gentle wash of shimmering keyboards and percussion textures, but by the time the tinkling bells enter on the bridge, the Brian Wilson symphonic dream-pop influences become too apparent, overshadowing Dungen’s approachable, idiosyncratic personality.

Fortunately, Mr. Ejstes doesn’t abandon that aspect of his band entirely. On “Finns Det Någon Möjlighet,” he orchestrates a fusion of the band’s two selves into a wonderfully tense and beautiful whole. The song starts off promisingly, with a pang of fuzzy guitar fading into a jaunty keyboard line and a brisk drum pace, before morphing into a swelling harmony between Mr. Ejstes’s voice and a piano. Strings fade in during the bridge, which is little more than a floating swatch of atmospheric mood. A gnarled guitar punch spices the second verse.

Halfway through the song, these contrasting attitudes — airy folk and crunching rock — collide and split like an atom, moving from folk to rock and back again right inside your ears. It’s a gorgeously arranged song in which Dungen’s two personalities don’t so much coexist as take turns showing themselves, neither gaining the upper hand. Unfortunately, “4” as a whole doesn’t follow such a fine example.