Close your eyes and think of an “epic” film score — blaring horns, sweeping strings, the heartbeat “bum-BUM” of a timpani. Big movies with big scores often draw on the Western canon, invoking the divine nature of classical music into scenes where a spaceship launches from Earth or anywhere from two to 200 guys fight with swords. What we may not imagine — but Trent Reznor and Atticus Ross do — is that an epic film score can sound like it should be played at the club.