In Brooklyn, New York duo Mountains’ stretched-out sonic wanderings, live instrumentation (including acoustic guitar, melodica, and accordion) arcs up against a weather-system of friendly electronic drones and field recordings of sounds like thunderstorms and rustling paper. All these elements don’t so much lock together as slowly work out some kind of harmonious agreement in the wordless mists of 2009’s Choral. The 2011 album Air Museum is a little more delicate and pure, blurring the line between acoustic and electronic music even further. That’s no small feat, considering it was also the band’s first record made in a studio. Brendon Anderegg and Koen Holtkamp started Mountains as a live project and don’t indulge in many overdubs, so they’re well-suited to give their sounds a big presence in person.