Sensurround

Sensurround is an audio technique developed in the 1970s by Universal Studios for the presentation of theatrical movies. According to Halliwell's Film Companion, the process involved "the augmentation of violent action on screen by intense waves of high decibel sound, enough, in some documented cases, to crack ribs." Originally developed as a showcase for the Universal production Earthquake, the process was used used in three subsequent films, Rollercoaster and Midway and in the cinema-adaption of Battlestar Galactica.

A Loud Reception

Sensurround involved the installation of at least 10 special very large subwoofer speakers in wood cabinets, which were placed in the corners of the theatre. The sound system was driven by a separate control box attached to a 1,600 watt audio amplifier. When triggered by a separate secondary pickup on the film's optical soundtrack, the system generated a sub-audible tone in the 60 cycle range at 120 decibels, the results of which could be "felt," but not "heard." The Sensurround speakers only played the Sensurround track, and did not play any of the film's soundtrack. In the case of "Earthquake," the Sensurround was activated during the quake scenes to augment the traditional mono soundtrack.

The much-hyped Sensurround made "Earthquake" a popular "event" film, but never caught on during the age of budding multiplex cinemas due to disturbances it caused at adjacent theatres. When Earthquake opened in November of 1974, The Godfather, Part II opened the same month, often playing in the next theatre auditorium. Theatre managers were inundated with complaints from audience members, literally shaken, by the bleeding of Sensurround into the theatre exhibiting Godfather II. This disruption was not worth the effort for most theatre owners, nor was the $500 per week Sensurround rental fee charged by Universal.

The excessively loud Sensurround also caused additional disruptions for theatres playing "Earthquake," including structural damage in some cinemas. The most famous example is that of Mann's Chinese Theatre in Hollywood, where theatre management strung a safety net over the seating to catch errant pieces of plaster after a test screening revealed Sensurround had actually cracked the ceiling. In Germany, Sensurround movies were only allowed to be played in single standing cinemas. When "Earthquake" was screened in Chicago, the head of the Chicago Building and Safety Department demanded that the system be turned down or removed, due to his concern that it would cause structural damage to city theatres.

Trivia

The alternative pop/rock band They Might Be Giants have a song called "Sensurround" which appeared on the soundtrack to the first Mighty Morphin Power Rangers movie and one of the band's EPs. Many fans consider "Sensurround" to be one of the band's best songs. The song makes several references to the theatrical audio technique.

"Sensurround" went thru several different versions as the technology evolved, including "Sensurround II" and "Sensurround III."

Contrary to popular belief, "Sensurround" cannot be "heard" (as a "rumble"), but it is rather "felt."

Current DVD prints of "Earthquake" do not feature a Sensurround track. Turning up the bass on an amplifier when watching the film will not yield the same results.