On the first two Fleet Foxes LPs, bandleader Robin Pecknold displayed a meticulousness that’s rare in indie-rock or folk—or any music, really. Every note was groomed to perfection, with songs constructed around billowing vocal harmonies that recalled Crosby, Stills & Nash—not in timbre, but in the way those voices snapped together like pieces of vinyl flooring. But it’s been six years since the band’s last album, the acclaimed Helplessness Blues, and a lot’s changed in the interim: Pecknold took time off to attend Columbia University, and drummer Josh Tillman fled to form his own, equally massive solo project, Father John Misty. Given that real-life context, the title of their new record feels worrying: Who cracked up and why? The messy opening seconds of “I Am All That I Need/Arroyo Seco/Thumbprint Scar” don’t ease those concerns: Pecknold croons in a low quiver, halfway in tune and barely audible, as his trademark harmonies struggle to merge into sync. That jarring presentation feels purposeful, a line in the sand. Much of Crack-Up is similarly raw, and often downright weird: The churning “Cassius” opens in an ambient atmosphere anchored by the looped sound of waves in a stream; abstract jazz-folk reverie “On Another Ocean (January/June)” fizzles out with several seconds of wailing saxophone. Still, no matter how much he experiments, Pecknold can’t completely run away from his obvious strengths. The album’s most stirring moments are those trademark vocal blasts (epic “Third of May/ Odaigahara”), bundled like summer flower bouquets.