Review: Duffy, ‘Endlessly’: Aidin Vaziri | Scientific fact: Blasting Duffy’s “Well, Well, Well” will send all cats within a 5-mile radius of the stereo scrambling for the Mexico border. Although impressively jaunty and stylishly retro, the first single from the petite Welsh singer’s sophomore album doesn’t exactly best serve her natural paint-peeling vocal range. Fortunately, the rest of the record does a better job revisiting the smoky, Lulu-inspired soul that helped 2007’s “Rockferry” move close to 7 million copies worldwide. Assisted by the Roots’ rhythm section and songwriting partner Albert Hammond Sr. (father of Strokes guitarist Albert Hammond Jr., writer of “To All the Girls I’ve Loved Before”), there’s not much room for error here (well, apart from “Well, Well, Well”). The effervescent opener, “My Boy,” ups the easy pop charms of her breakthrough hit, “Mercy,” while the disc’s centerpiece, “Endlessly,” sounds like a karaoke bar version of “To Sir With Love” with the wrong lyrics scrolling across the screen.