Complex sentence: For theaters that did not install the Sensurround system, the original mix utilized extensive surround effects and mag stereo prints had the 12-kHz CinemaScope'switching' tone included on the surround track to reduce hiss heard from the surround speakers.
Split into simpler sentences: For theaters that did not install the Sensurround system, the original mix utilized extensive surround effects. Mag stereo prints used the 12 kHz CinemaScope'switching' tone included on the surround track to reduce hiss heard from the surround speakers.