Theaters Installed

           This signal was then amplified greatly and played into the cinema through massive sub bass speaker cabinets, which literally shook the thereat. There were cases reported of pieces of ceiling falling down in some of the older theaters that installed the system. The system was designed for those three films and has never been used since. Dolby in the mean time were going from strength to strength and had revitalised the sound side of the industry. Having improved optical sound they then looked at 70mm magnetic, firstly employing noise reduction and secondly devising a system which used the two inner tracks for sub bass signals giving an effect similar

to Sensurround as well as adding stereo surrounds  channels. Used experimentally for Warners' film  Superwoman' at the Empire, Leicester Square in 1978 and then on a world wide basis for 'Apocalypse Now', a year later. However, it was Dolby's optical stereo system which took the industry by storm, and became the industry standard. Cinemas world-wide began upgrading to stereo particularly the newly built American Multiplex style of cinemas. With this new building programme audiences were beginning to grow again, but the new audiences were younger people who were more aware of sound quality. With the advent of digital sound at home with the Compact Disk it was not long before this new audience was demanding the same quality of sound from the cinemas.