Tripper, the Fruit Bats’ 2011 follow-up to The Ruminant Band, is more pared down, with bandleader Eric Johnson doing most of the legwork himself. Synthesizers and keyboard loops replace the knotted guitars. Atmospheric washes of sound replace the sunny, straightforward hooks. On songs like “The Fen,” instruments replace vocals entirely, sounding more like a clip from an orchestral movie soundtrack than the work of a rock band. The majority of the work was done by Johnson and producer Thom Monahan, resulting in a layered sound that stacks overdubbed harmonies onto combinations of pump organ, found sounds, acoustic guitar, and various bleeps and bloops. Whether he’s working alone or leading a full lineup, though, Johnson knows his way around a good pop hook, and Tripper’s best songs are rooted in catchy, sunny melodies that shine through their heavy wrapping paper. Proof that Johnson knows how to stretch his legs without losing his balance.