SARAH JAROSZ Sarah Jarosz is a refreshing change from the balladry and bombast of radio mavens like Adele and Florence Welch. With a smoky voice and understated style, Jarosz weaves her songs (and the occasional Radiohead cover) amid mandolin, clawhammer banjo and guitar, all of which she plays herself. Her folk-pop often shares the doleful tone of old-timey Appalachain tunes, but it's balanced by her spirited, virtuosic talent, especially on the mandolin. Not bad for a gal who's not even out of college yet. $49.50 and up. Knight Theater.