I’m recalling a “Sound It Out” series trio gig by the pianist that honed in on the knotty particulars that have become part of his signature sound. As a composer Mitchell is smitten with the kind of intricacy that takes a sec to grok. When the kaleidoscope focuses, however, the payoff is big. He’s swung hard with Dave Douglas, waxed turbulent with Tim Berne, and dropped a killer duet album of abstract etudes called Fiction. This outing, with Chris Speed on sax, just might be an unholy combo of all three approaches.