Sensurround
Sensurround is a multi-channel magnetone process for the reproduction of particularly low tones in movies as a sound effect (4.1). These oscillations are perceived as vibrations and serve to reinforce the impression of explosions, shocks, strong motors, etc.
It was 1974 for the Universal production earthquakes ( Earthquake developed), reaching deep tones down to 15 Hz . There were different standards for accommodating the sound on the film strip: 6-track magnetic sound for 70 mm film , 4-track magnetic sound for 35 mm film and an optical optical sound track for older 35 mm projection systems.
The Sensurround system required a special decoding box in the cinema, several amplifiers with 1000 watts of power and ten large, specially adapted bass speakers ( subwoofers , which were set up in equal parts in the front and back of the hall) with a sound pressure level of around 100 to 120 dB (A) generated.
The effect in the movie Earthquake was very realistic (but above all loud). In some areas, viewers are said to have thought that an earthquake was actually occurring. In older cinemas, the strong sound pressure caused the dust to trickle down from the ceiling, giving the film Earthquake a special touch. In a cinema in the US city of Hackensack, part of the ceiling even fell down during the screening of the film Roller Coaster and damaged ten seats that no one was sitting on.
Because of the low-frequency tones, films in Sensurround in Germany should only be shown in individually standing cinemas, as the low-tones affected neighboring cinemas.
Films in Sensurround
- Erdbeben ( Earthquake , 1974) The DVD version contains, according to the cover, the original Sensurround sound.
- Battle for Midway ( Midway , 1976)
- Roller coaster ( Roller Coaster , 1977)
- Battlestar Galactica ( Battlestar Galactica , 1978)
- Mission Galactica ( Mission Galactica - The Cylon Attack , 1979)