The Wilson sisters have proven adept at re-inventing and repackaging themselves without really changing what they do. Heart was the breakthrough female rock act of the 1970s. A decade later, it answered the call for video vixens and power ballads. While the band has not been exactly dormant, “Fanatic” marks an ambitious overture beyond the base of loyal fans. A key player as producer and second guitar is Ben Mink, who has given a boost to the sound of both k.d. lang and Feist. With Ann’s voice as powerful as ever, the songs are bracing and varied enough to signify a genuine renewal. “Skin and Bones” in particular reveals a sense of fun not always evident on the comeback trail.