Santa’s sleigh may be the most famous vehicle associated with Christmas, but the Steamroller is a close second. Since the '80s, Chip Davis’ new-agey ensemble has reimagined the wintry fantasias of classic Christmas carols as prog-rock synthphonies, transforming holiday standards like “Carol of the Bells” and “Hark! The Herald Angels Sing” into veritable sci-fi video-game soundtracks. But for all its futurist flair, Mannheim Steamroller’s Christmas repertoire radiates the joy and enchantment of the season, while a meditative interpretation of “The First Noel” exudes the humbling sense of gratitude we should all feel as the year comes to an end.