As HeavyShift, the British duo of keyboardist William South and saxophone specialist John Wallace infuse The Conversation with welcome doses of sly musical wit, as well as memorable hooks and excellent musicianship. In the hands of lesser talents, a gliding groove tune like “Oxo Cubed,” for example, could be just another nice-but-impressionless smooth-jazz confection, but Wallace’s dusky sax adds edge and substance. Details like the retro-organ whir and snaking, low sax line of “A.M.” make these compositions memorable and fun. From the kicking, rolling surf-jazz of “Georgie’s Frame” to the strutting rhythms and hard-spiraling sax of “Bird Meets Norm,” this duo shows the smarts and spirit of ska-pop wiseacres Madness in a jazzy, technically polished package. Throughout The Conversation, South and Wallace keep listeners guessing, with even more reflective pieces like the dark “Song for My Father” revealing slightly off-kilter, blue layers of intrigue.