RSO Conductor David Wiley does a double take as performers sail above the stage during last week’s “Rock Symphony Cirque” at the Salem Civic Center. In only its second season, the show has already become a big fund raiser for the symphony and was nearly sold out this year as word has spread about its unique combination of symphony-backed rock music and high flying acrobatic performances. This year’s theme celebrated “50 Years of Motown” with the fast paced accompaniment of “Jeans and Classics.”