Return of the Jedi, in 1983, was the first motion picture to be released in concordance with the new "Lucasfilm Seal of Approval". The THX theater sound reproduction system grew from an idea to install a state-of-the-art monitoring system for Lucasfilm's new re-recording stage. The system's unequalized frequency response was extended down to the 40Hz third-octave band, down one and a half dB, which was an octave better than most theater loudspeaker systems. Treble response was also extended in the octave above 8kHz. Not only were the crossover and sound system marketed, but also a complete theater inspection package that would be marked under the tradename of the THX System. Theaters who pursue THX approval must meet several criteria. They must meet specifications for reverberation time versus volume, picture sharpness, noise limits, and screen properties. In addition, 70mm film houses were required to install a Kintek KT-9 subwoofer.

In the early eighties ('81-'82), Peter Custer and Dr. George Bird developed and patented Digital Fluorescentsound, one of the earliest attempts to incorporate digital sound with motion pictures. Digital fluorescent soundtracking is a high-data density digital sound record multiplexed with the picture -- the digital information was actually printed on the picture. It was invisible on the screen, but when excited by long-wave ultraviolet light in a readout stage that retrofits into the magnetic track penthouse position on the projector, the surface of the film emits bright blue visable light, with that image scanned, corrected and reproduced as six channels of analog signal without distortion or noise.

Dolby SR was introduced in 1986 as Dolby's second generation professional recording system. Not only was it designed to provide more noise reduction but it also provides a number of other technological innovations that extend the recording's dynamic range and gives the user a master recording that is indistinguishable from live sound. SR is therefore referred to as a signal processing system rather than just a noise reduction system. Dolby began to manufacture equipment which incorporated SR and began selling it to the recording and film industries. In 1987, Robocop  and Innerspace were the first films to be released with Dolby SR.

 Created by Jonathan Kay, Kimber Ghent, Brian Chumney, and Erik Lutkins

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