User manual LEXICON CP-3 PLUS THEORY AND DESIGN REV 2

[. . . ] CP-3PLUS Theory and Design Lexicon Acknowledgements The CP-3PLUS is manufactured under license from Dolby Laboratories Licensing Corporation. Additionally licensed under one or more of the following patents: U. S. numbers 3, 632, 886, 3, 746, 792 and 3, 959, 590; Canadian numbers 1, 004, 603 and 1, 037, 877. "Dolby" and the doubleD symbol are trademarks of Dolby Laboratories Licensing Corporation. [. . . ] This technological breakthrough, which allowed four channels of sound to be recorded onto the two available optical soundtracks of a 35mm movie print, yielded spectacular results -- and created a demand for improved film sound tracks, and for better-sounding theaters. Theaters that upgraded their sound systems were rewarded with larger audiences. Over the next decade, Dolby Stereo became an established standard for film sound recording -- but theater sound systems, although improved, varied in their ultimate accuracy. In the 1980's a new movie theater sound system was created under the name THX. This system addressed, for the first time, the design of a theater speaker system which could faithfully reproduce the film director's intentions. The THX Sound System complemented and enhanced the playback of Dolby Stereo, and encompassed standards for power amplifiers, speakers, and the acoustics of theaters themselves, to assure the best possible reproduction of movie soundtracks. By 1990, this system was available in over 500 theaters across the country. The recent availability of film on video tape has led to a demand for home audio/video systems which equal the best theater sound. The Home THX Cinema system was designed to address this need, and the CP-3PLUS incorporates it into the THX mode. The variety of CP-3PLUS surround film modes allows you to have the highest possible sound quality for video material -- whether you select classic monaural movies or the latest releases with all of their special effects -- simply by changing modes. 16 CP-3PLUS Digital Surround Processor CP-3PLUS Theory and Design Mono Logic Mono Logic is a surround conversion mode for monaural film sound tracks. A quick look through any video rental selection will prove the usefulness of such a mode; a large percentage of titles are mono. The problem of mono-to-stereo conversion is an old one. One time-honored solution is to break the incoming signal into frequency bands, sending some to one channel and the rest to the other. When the filters are complementary (when the sum of the two output channels equals the original input channel) this solution can give stereo spread without ruining the tonal balance. When the filters are non-complementary, they can produce an unpleasant fake stereo effect. Some effort has been made to design filter pairs for film sound which leave voice frequencies unchanged while spreading out the music. More recent designs have gone in another direction, using digital or analog delay lines to produce a comb filter effect. So far, these attempts have not been very successful. The principal element of film sound is dialog and the principal rule in reproducing it is to assure that it appears exclusively in the center channel. Broadcasters, who have an interest in converting mixtures of dialog and music to synthesized stereo, have built circuits designed to turn off the stereo synthesizer when voice appears. Unfortunately, the switch from mono to stereo is often abrupt and the chances of dropping into mono by mistake during music are high. One basic problem with films, especially modern ones, is that music or background effects which should be spread out into the side speakers frequently appear at a low level beneath the dialog. [. . . ] Once you have selected a location, press STORE. It's fun, and pretty easy, to create almost any acoustic space you want. For the megalomaniacs among you try creating your own private Taj Mahal -- in the Cathedral preset, increase MID RT to 11. 2 and turn EFFECT LEVEL all the way up. Play a CD for a couple seconds, then hit pause and close your eyes . . . [. . . ]