American Conductor John Mauceri. He is the host and narrator of a new PBS Great Performances documentary, "Music for the Movies: The Hollywood Sound." Mauceri also composes the BBC National Orchestra of Wales in music from Hollywood films from the 30's and 40s'. (The documentary airs tonight at 9:30). Mauceri is currently music director of the Hollywood Bowl Orchestra in L.A. He has two new CDs: "Between Two Worlds: Music of Korngold," and "The Sound of Hollywood: Music From the Movies" (both on London records).