Angel Olsen has been nothing if not transparent about the path that led to “All Mirrors.” She’d initially planned to release two versions of the same album, one a “raw and real” solo outing, and another with a full band. Somewhere on the way toward the latter version, a 14-piece orchestra came into the picture — and the end result is this towering, tempestuous album, where nearly every song has calms and storms matching Olsen’s soaring voice and intricate melodies. (The album is so arresting that it’s easy to understand why the solo version has been rescheduled for some time next year.)

Over the course of her three preceding albums, Olsen established herself as one of the most promising indie-leaning singer-songwriters of the past decade, with a powerful and versatile voice she uses strategically, belting, murmuring, singing plaintively or emotionally as suits the song. And while “All Mirrors” is distinctively Olsen, it smashes the mold of everything that came before. Where before she conveyed intensity through her voice and a conventional rock-band format, here there’s deep-valley echo on her vocals, crashing cymbals and a looming orchestra that rages like an angry sea, creaking and groaning; or, conversely, providing a plush, swooning setting for softer songs like “Tonight” that still has a few lightning bolts toward the end.

According to Olsen’s “statement” that accompanies the album, the songs here are “about losing empathy, trust, love for destructive people… about walking away from the noise and realizing that you can have solitude and peace in your own thoughts, alone, without anyone to know it or validate it… about owning up to your darkest side, finding the capacity for new love and trusting change even when you feel like a stranger.” Be that as it may, the album is intense and diverse, and at nearly all points sounds really, really big — or on the verge of sounding that way. Copiloting this venture with Olsen were John Congleton — a St. Vincent, Erykah Badu and Sharon Van Etten vet with whom she worked on 2013’s “Burn Your Fire for No Witness,” and who is becoming one of the most adventurous producers working today — and arranger/musicians Jherek Bischoff and Ben Babbitt.

“All Mirrors” is not an orchestral album; it’s a rock-leaning singer-songwriter album dominated by orchestral and synthesizer arrangements, with drums and guitars generally relegated to distant secondary roles. And although the album has a unified sound, many of the songs are very different from each other — the two openers, “Lark” and the title track, are the best examples of the sturm und drang described above, but there are softer songs throughout, and the two closers, “Endgame” and “Chance,” almost sound like torch songs from the 1940s or ‘50s, with the orchestra providing a more playful and, dare we say, romantic accompaniment.

It’s been an interesting year for orchestral-leaning pop/rock albums — the latest from Karen O and Danger Mouse, Lana Del Rey and Weyes Blood come to mind — but those outings don’t have the orchestra as deeply as the core as this one does. It will be a challenge for Olsen to render these songs in a live setting, as she’ll be doing all across North America this fall and Europe in the spring — but if “All Mirrors” is any indication, it’ll be monumental.