There’s no need to be unimaginative when it comes to nonsense background vocal syllables; why sing “ba ba ba” or “shoo be do bop” when you could go with “yip yip way bop de boom ditty boom ditty”? Johnnie Ray’s “Yes Tonight Josephine” goes there. The best doo-wop groups find similarly creative ways to use the voices at their disposal, from the staccato bursts of “I Only Have Eyes For You” to the soothing dum-dums of “The Old Lamplighter.”