With their stark single-note piano theme, Trent Reznor and Atticus Ross found a sound that mirrors the roiling emotions lying just beyond the cerebral tensions of The Social Network. The percolating techno track “In Motion” conveys the programming obsessions and vertiginous success of a tech company, while the throbbing and abrasive “A Familiar Taste” channels underlying urges of greed, corruption, and selfishness. The duo’s unnerving balance of delicateness and animosity is best experienced on the frighteningly sleek interpretation of Wagner’s “In the Hall of the Mountain King.”