Pianist Brad Mehldau's so-so excursion into atmospheric pop production, Largo, may be proving to be a worthwhile experiment after all. Having gotten that out of his system, at least for the moment, he sounds looser in the pocket than he has in a long time in returning to the ruminative piano trio format with which he made his reputation. In applying some of his quirkiest personal touches to jazz and pop standards, he also sounds--no offense intended--more awake. Hooking up with his longstanding rhythm mates, bassist Larry Grenadier, and drummer Jorge Rossy, Mehldau offsets his patented lyrical touches with antic minimalist strokes, bold vamps, and high-stepping two-hand strategies. Alternately spiky and seductive, his unaccompanied playing on an initially languid “Get Happy“ is a winning case of the left hand pretending not to know what the right hand is doing. Reharmonizing Charles Chaplin's “Smile“ with dense harmonic clouds, he properly obliterates that hoary melody. There's another sighing Radiohead treatment, “Everything in its Right Place,“ and an attempt at enlivening Paul Simon's “Still Crazy (After All These Years),“ but it's his happy time with Thelonious Monk's “Skippy“ that tells us his best may be yet to come.