By Peter Valelly

Once a sitcom and soap opera actress in her native Argentina, singer-songwriter Juana Molina has an unlikely background for one of the best musicians in recent memory. But her past as a performer may help explain her playful and mischievous sound. Over the course of five albums, Molina has unveiled a style and sensibility that is at once wildly inventive and utterly palatable. Molina’s songs are usually composed of a knotty songwriting structure adorned with gentle folk guitar, soft singing en español, and unexpected billows of chopped and distorted vocals and avant-garde tape manipulation-a simple recipe, but one which has kept the singer rampantly adventurous and playful from 2002’s great “Segundo,” a not-quite-straightforward wedding of electronica and folk, to the gnarlier and richer sonic constructions of “Tres Cosas” and “Son.”With her fifth album “Un Día,” released on Tuesday,” Molina seeks to remedy what some had perceived as a deficit of rhythm in her music. “All that was insinuated in the past is now more tangible, hearable,” she has said of the new album. Indeed, the title track, which also opens the album, makes rhythmic playthings out of Molina’s whispery vocal twitches, swaths of acoustic guitar, strange effects, rumbling drums and a swarm of raucous horns. At the heart of the song is a more impassioned vocal than Molina’s ever used, soaring and inviting.

Elsewhere on the album, the newly emphasized rhythms are less bombastic but equally brilliant. “Lo Dejamos,” with its elastic bass sounds and barely-there vocals, is lent texture and suspense by washes of cymbal and aimless and sinister guitar plucking towards the end. Later, on “Los Hongos de Marosa” and the thoroughly deranged “Dar (Qué Dificil),” the use of the human voice as a percussive sound culminates in a gloriously uneasy heap of vocal tics, clicks and moans. The angelic “No Llama” starts out delicate before gaining speed and percussive heft to become one of the album’s most alluring songs.

The album has fewer tracks than all of Molina’s previous ones, and the songs are generally longer. This allows for each track to build and stretch, to sustain tension and to work towards a climax, or many (or, for that matter, none). The exemplary track in this regard may be “Vive Solo,” also the album highlight. Beginning with sunny and melodic vocals and plaintive, throbbing chords, it grows more and more layered as it grows faster, more intense, more driving. Molina’s vocals start to splinter into weird licks of sound that agitate, stammer, swarm, and interlock into something strangely redolent of Animal Collective.

The autumnal atmosphere and rich, radical sonic textures of “Un Día” are a refreshing combination in what has been a fairly unexciting-although far from dismal-year for music. Even as we slide into winter, the record’s abundance of sunburnt guitars and ethereal vocals provide an exciting respite. Juana Molina, no longer a fringe artist to keep your eye on, has arrived as one of the brightest and most inventive musicians of the last ten years, which hopefully means that people will pay attention to her and to this fantastic album.