DOLBY AND THX IN THE HOME
When you walk into your home theatre retailer you'll see both the THX
and the Dolby Surround Pro Logic logos on a broad range of equipment
choices.
 What do these two logos mean, and how do these two technologies work
together?
It's important first to understand that Dolby and THX are not
competitors. In the movie theatre, Dolby equipment is at the core of the
"A" chain of a movie theatre's sound system, the equipment installed in
the projection booth to read the soundtrack from the film, decode it,
and process it. Lucasfilm's THX division develops technologies and sets
standards primarily for the "B" or "playback" chain that is, basically,
the theatre's amplification and loudspeaker system, and the acoustics of
the auditorium.
The relationship between the two in a home theatre environment is much
the same. Without going into the technical details available elsewhere
on this Web site (see Principles of Pro Logic Decoding), the Dolby
analog soundtrack information "comes along for the ride" as a movie is
translated from the big screen onto laserdisc or VHS videotape. Home
viewers equipped with the appropriate speakers and a Dolby Surround
decoder (which may be a stand-alone component or a built-in feature on a
television set or laserdisc player) can recover that information and
enjoy playback through left, center, right and surround channels, just
as in the movie theatre.
Home theatre equipment which has gained THX certification takes this a
step further, by incorporating technologies and characteristics which
allow the home theatre environment to accurately recreate the film
mixing stage where the soundtrack was created, allowing you to hear
that soundtrack as the filmmaker intended. A visit to the THX Web Site
can tell you more about the certification process and goals of the Home
THX program. But there is literally not a THX home theatre system which
isn't built around Dolby Surround Pro Logic capability ... just as by
far the majority of THX movie theatres are Dolby installations.
     Are non-THX home theatre systems possible?
Of course . . . and only you can determine what system will best suit
your interests, space and budget. But any exploration of your home
theatre options should include a look at both Dolby Surround Pro Logic
and THX, since together the two can offer you a very exciting
sound-with-picture experience. (You will also want to consider whether
upgradability to Dolby Digital (Surround AC-3), the new digital sound
technology based on the Dolby Digital movie sound format and now
available for the home, is important to you.)
Copyright © 1996 Dolby Laboratories, Inc.
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