Founded in 1991 at Tufts University, Guster won its fan base the old-fashioned way: taking to the road until it achieved status among followers of jam bands and alt-rockers. In the studio, it worked slowly, during the course of 23 years releasing only six full-length studio albums of mostly bright, hooky songs featuring the sweet voices of guitarists Adam Gardner and Ryan Miller rising above their chugging acoustic instruments and Brian Rosenworcel’s percussion. Throughout the new album, the trademark well-strummed acoustic guitars have been replaced, much as the prior albums’ directness has been nudged aside for a sense of melodrama. Mr. Rosenworcel’s drums are still prominent, though Mr. Swift used only two microphones to capture their sound. (Other producers might have used many, many more.) The new approach is apparent instantly: The opener, “Long Night,” unfolds deliberately behind a steady rhythm and a falsetto vocal accompanied by a xylophone and waves of slide guitars. With a touch of prog-rock-influenced electronic music, “Endlessly” features echoey vocals with textured percussion below. The driving, modestly funky “Simple Machine” bounces along on bubbling synths and clacking percussion. All-star sideman Jon Natchez contributed reeds and trombones.