A talented cast, stirring vocals, athletic dance numbers and vigorous direction supply crowd-pleasing elements in the lively new musical, 'Memphis,' as evidenced by the waves of appreciation coming off the audience. But there's also a nagging predictability to this story of a white DJ who brings rockin' rhythm and blues from black Beale Street to the mainstream in 1950s Tennessee. The show is entertaining but synthetic, its telepic plotting restitching familiar threads from 'Hairspray' and 'Dreamgirls,' while covering fictitious ground adjacent to that of recent biopic 'Cadillac Records.'