new sound mix was commissioned, keeping the music and dialogue   intact, and adding new effects for almost all scenes. For example,   Enterprise Computer voice alarms are now replaced with klaxon sirens, the   lightning effects have new echoes, and a blend of Enterprise bridge sound   effects from the original _"Star Trek"_ (1966), _Star Trek II: The Wrath of   Khan_ (1982), and _Star Trek VI: The Undiscovered Country_ (1991) have been   added into the background of scenes taking place on the bridge. The new mix   is in Dolby 5.1 EX Surround. 