Boston indie rock band Pile’s sixth album is a genuine surprise. Stark but warm, dingy but pretty, Hairshirt recalls the dreamy side of ’80s Sonic Youth paired with a melancholy grandeur that could only be called Pile’s own. The sound is stripped down—bass, drums, guitar—but the songs are fragmented and surprising, taking detours through blues and post-punk (as on the labyrinthine “Rope’s Length”), Jesus Lizard-style churn (“Hairshirt”), and almost Beatles-esque gentleness (“Worms,” “Dogs”).