To clarify a popular misconception, Dolby and THX are not competing sound systems. Rather, the two coexist in high-quality theatres the world over to bring you the very best sound experience possible.
There are two subsets of equipment which comprise the sound system in a theatre. The "A" chain consists mainly of the equipment installed in the projection booth to actually read the soundtrack from the film, decode it, and process it. The signal that results is fed to the "B" chain -- that is, basically, the theatre's amplification and loudspeaker system.
The professional cinema equipment manufactured by Dolby Laboratories is used in the "A" chain: cinema sound processors for converting the analog and digital sound information on the filmstrip into high-quality audio. Lucasfilm's THX division sets standards primarily for the "B" chain, including loudspeaker placement and the acoustics of the theatre auditorium. To obtain THX certification, a theatre must comply with those standards and also make use of equipment from THX-approved manufacturers. All Dolby cinema processors are THX-approved, and by far the majority of THX theatres are Dolby installations.
What does this mean for you as a moviegoer? That if you see both the Dolby and THX logos on the theatre marquee or in the newspaper, it's not a mistake: Dolby and THX can and often do go together. Neither is "better" than the other, but different and complementary, and Dolby soundtracks played back in THX auditoriums will give you a sound experience that is exceptionally close to what the filmmaker intended. Wherever possible, look for theatres that offer both Dolby Digital and THX, since the added dynamic range and frequency response a Dolby Digital soundtrack provides benefit greatly from playback in an auditorium that meets THX specifications.
What's more, both Dolby and THX are sound advantages you can enjoy in your home as well as at the movies. In home theatre, Dolby Surround Pro Logic is the core audio technology for surround sound and Home THX components optimize the reproduction of film soundtrack material. See our Home Theater section for more information.
Visit the THX web site to find out more about the Lucasfilm THX program both in movie theatres and in the home.
