When accordion player Juancho de la Espriella and singer Martín Elías get together, their music invokes not just creativity, but combustion. On El Boom del Momento, the result is modern vallenato at its most beautiful and delirious. Just as Juancho pummels the title track with a barrage of rhythmic riffs, Elías sings “Tu Loco” with such enthusiasm that he practically goes hoarse. “Por Ti” starts out as a heart-wrenching ballad before stopping on a sixpence to become, of all things, a jubilant, percussive parade.