Acoustic guitars get a bad rap. Far too often, they’re strummed in a banal fashion that adds little to the song beyond a chorded backing. Alejandro Escovedo and David Polkingham showed that acoustic guitars don’t have to be boring as Escovedo emphasized the rhythm while Polkingham picked up parts that Escovedo often assigns to members of his string quartet. As a result, songs rarely felt like the Cliff’s Notes for fuller versions, and nothing demonstrated that like “Baby’s Got New Plans,” which started with a traditional structure, but in the extended instrumental sections, the two toyed with tension and release and harmony and dissonance. The set similarly worked against conventions, blending different lyric modes. There were confessional family stories, but Escovedo also performed tersely worded dramas and richly evocative poetry. On paper, that might sound like a lot of braininess, but in performance, the songs were often beautiful and emotional, with memorable, subtle melodies.