Mago, a duet LP for Medeski, Martin, and Wood’s two Ms on M #2’s Amulet imprint, sounds positively old guard. This is a strange sensation, if only because the trio has spent the past two decades pursuing the genre’s outer edges. Amazingly, though, the mainstream of jazz progressed right along with them. By now, the instinctive meld between Billy Martin’s liquid drumming and John Medeski’s Hammond splatterings no longer pricks antennae like it once did, though it is no less brilliant. On “Crustaceatron,” Medeski paints in sample-like snatches over Martin’s room-filling beats (dubbed helpfully by producer Danny Blume). On the disc-closing “L’Aventura,” the two trade roles like the musical intimates they are, Medeski’s clumped phrasings becoming the track’s rhythmic bedrock while Martin’s propulsive melodic motion motors the jam forward. Elsewhere, such as “Apology,” the playing is sluggishly casual. Even during this most laid-back session, though, there are surprises to be found, like Martin’s wild, distorted jass break in the midst of “Hot Little,” or Blume’s compactly engineered space-out, “Syncretism.” Medeski, Martin, and Wood changed the face of American jazz, though that’s probably not what Martin and Medeski set out to do when they first jammed together in 1989. They probably set out to make Mago.