This Portland duo broke into the indie-music mainstream in 2009 with “See Mystery Lights,” a set of brainy electro-funk songs inspired in part by the unexplained illuminations observable after dark over Marfa, Texas. Yacht extends that fusion of the high-minded and the street-level on its excellent follow-up effort, “Shangri-La,” which opens with back-to-back disco-rock bangers laying out the band’s thoughts on the future of civilization. The first is called “Utopia” and the second “Dystopia,” but they both sound like emanations from a better place. Yacht has said that it recorded “Shangri-La” in a more professional setting than it did “See Mystery Lights,” and indeed the new album offers plenty of top-shelf headphone fodder. Check out, for instance, the delicious way an ascending backing-vocal part contrasts with a descending electric-piano riff near the end of “I Walked Alone.” Yet it’s not the exquisite crispness of Yacht’s bass lines that makes “Shangri-La” so appealing (though that certainly doesn’t hurt). Rather, it’s the band’s knack for giving weighty ideas the lighthearted gift of groove.