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Home THX Cinema is a surround playback technology advocated by Lucasfilm of the United States, a company famous for the sound effects of
such movies as Star Wars and Indiana Jones. This technology was born from the desire of movie director George Lucas to create the ultimate
theater experience. THX Cinema technology includes both a design and performance certification program for movie theaters and a separate
design and certificatioin program for home theater equipment.
The THX Cinema program for theaters is used in over 3000 movie theaters throughout the world and is highly reputed for both its sound and
picture quality.
The Home THX program includes proprietary Lucasfilm technology, coupled with an extensive certification process, which provides the listener
with the most realistic reproduction in the home of motion picture soundtracks. Differences between the dubbing stage (sound mixing
environment) and the motion picture theater are compensated for in home playback environments by the unique THX post-processing functions.
THX is not a multi-channel encoding/decoding system (like Dolby Digital or DTS), but is a set of functions that enhance and improve upon the
multi-channel decoded audio program material. So, for the best motion picture surround sound reproduction, choose THX with Dolby Digital,
Dolby Surround Pro Logic or DTS. The THX processing can be de-activated at the touch of a button when listening to non-movie surround sound
programs, such as music concerts, etc.
“THX 5.1” indicates the combination of a digital discrete multi-channel motion picture soundtrack as well as the specific THX multi-channel audio
post-processing.
DENON was the first company in the world to offer THX 5.1 processing in a home theater component. The AVR-5700 is the world’s first A/V
receiver that incorporates the ability to have THX 5.1 surround sound with either Dolby Digital or DTS encoded programs.
The THX processor achieves clear dialogue, more effective sound positioning and directivity and a wide dynamic range. On the AVR-5700, when
the Home THX Cinema mode is turned on, THX processing is automatically added after signal processing by the Dolby Digital, DTS, or Dolby Pro
Logic decoder. The THX processing consists of the main components described below.
(1) Re-equalizer:
In general, sound for movie theaters is recorded under the premise that the front and center channels will be output from behind the screen
and that the sound will be played in large spaces that include many objects that absorb sound (movie theater seats, etc.). Because of this, the
sound characteristics, particular the high frequency response, differs when the same soundtrack is played in the home (it can sound overly
bright and harsh). The re-equalizer is a circuit that provides the compensation necessary to achieve natural high frequency sound in the home
that matches that heard in the movie theater.
(2) Timber matching circuit:
The human ear is directional, so the sound from a speaker set in front of the listener will seem different from the sound from the same
speaker set at the listener’s side. The timber matching circuit compensates for this, and particularly provides a natural sense of movement
when the sound moves from the front to the surround and vice versa.
(3) Dynamic decorrelation circuit:
In movie theaters, surround signals come from two banks of surround speakers, placed at the sides and at the rear of the theater. By using
multiple loudspeakers in each surround bank, the audience hears the intended surround effect regardless of where they sit in the theater.
Even with 5.1 soundtracks, surround sound information in the motion picture soundtrack is often monaural (sounds are common to both
surround left and surround right channels). In the theater, the use of many surround speakers “spreads” the surround information over a wide
area, minimizing the ability to localize the sound from a particular speaker. In the home however, monaural information in the soundtrack
often provides an unusual result, with the surround sound strongly localized directly at the listening position, and is not perceived as
enveloping, spacious surround sound as heard in the theater. The dynamic decorrelation circuit constantly monitors the content of the
surround channels, and when monaural surround information is present, processes the sound to derive different signals that are sent to the
left and right surround speakers. This provides rich, spacious and enveloping surround sound. The decorrelation circuit is always activated
when listening to Dolby Surround Pro Logic programs, since the Pro Logic surround channel is always monaural.
THX 5.1 standards are extremely strict performance standards for AV amplifiers. Over 300 different performance parameters are checked,
covering virtually all aspects of the component’s performance, including use and operation, along with critical tests and measurements using
specialized test tones along with highly revealing program material. The AVR-5700 is certified compliant with THX-ULTRA, Lucasfilm’s strictest
standards, a sign of quality assurance indicating that it offers the ultimate home theater performance and sound quality.
“Lucasfilm” and “THX” are registered trademarks of Lucasfilm.
This set manufactured under license of Lucasfilm.
Home THX Cinema surround mode
