Maybe this modern soul duo should have entitled their second CD Predictable. Though sisters Tina and Erica (neither is a Mary) can sing, they work the same tired hip-hop grooves and lovestruck lyrics as homogenized R&B radio. One thing is incredible about Incredible, though — it’s G-rated. They sing about self-esteem and spiritual devotion (their last CD won a Grammy for Best Contemporary Gospel Album). That won’t earn them a spot on sex-obsessed MTV, but hey, they’ve got connections in higher places.