The idea of chamber rock began in the 1960s with The Beatles leading the way. Seldom has the concept been realized as well in recent years as on Joe 2.0’s CD. The Milwaukee sextet, led by violinist Joe Ketchum and fronted by Cheap Trick’s original singer, Xeno, features two violins, a viola and a cello as well as drums. With a wonderful mix of acoustic and switched-on strings, the group folds the melodic drama of a classical string quartet into compact, rhythmical pop-rock. There are echoes of Roy Wood, The Left Banke and that heady phase of ’60s rock when even the Stones flirted with the Baroque.