I am thinking this has nothing to do with Surround Sound etc. My guess is that he will be working on ways to get better audio quality out of Apple's compressed format both audio and video.
Tom Holman is a marketing hack, and not an engineer. THX was a bad joke on the movie business, and you'll note has mostly disappeared. Most of Holman's ideas are long since discredited - read Dr. Floyd Toole's book surround sound where he guts Holman like a fish.