|Privately held company|
|Headquarters||San Rafael, California, United States|
|George Lucas, Founder
Tomlinson Holman, Developer
David Pierce, General Manager
Richard Dean, VP Technology
Robert Hewitt, VP Sales
|Products||Digital Audio Certifications
Digital Audio and Video Mastering Technologies
Lucasfilm Ltd. (1983-2001)Creative Labs (2001-present)
THX Limited (THX Ltd.) is a American high-fidelity audio/visual reproduction standard for movie theaters, screening rooms, home theaters, computer speakers, gaming consoles, and car audio systems. The current THX was created in 2002 when it spun off from Lucasfilm Ltd. THX was developed by Tomlinson Holman at George Lucas' company, Lucasfilm, in 1983 to ensure that the soundtrack for the third Star Wars film, Return of the Jedi, would be accurately reproduced in the best venues. THX was named after Holman, with the "X" standing for "crossover" as well as in homage to Lucas's first film, THX 1138. The distinctive glissando used in the THX trailers, created by Holman's coworker James A. Moorer, is known as the "Deep Note".
The THX system is not a recording technology, and it does not specify a sound recording format: all sound formats, whether digital (Dolby Digital, SDDS) or analog (Dolby Stereo, Ultra Stereo), can be "shown in THX." THX is mainly a quality assurance system. THX-certified theaters provide a high-quality, predictable playback environment to ensure that any film soundtrack mixed in THX will sound as near as possible to the intentions of the mixing engineer. THX also provides certified theaters with a special crossover circuit whose use is part of the standard. Certification of an auditorium entails specific acoustic and other technical requirements; architectural requirements include a floating floor, baffled and acoustically treated walls, non-parallel walls (to reduce standing waves), a perforated screen (to allow center channel continuity), and NC30 rating for background noise ("ensures noise from air conditioning units and projection equipment does not mask the subtle effects in a movie's soundtrack.")
THX was owned by sound card manufacturer Creative Labs, which holds a 60% share of the company. The company has had a long history with Creative, and was responsible for the creation of the first THX-certified audio card for computers, the Sound Blaster Audigy 2.
THX has created a certification process for additional products including home audio, home theater, video, and automotive sound components and products. THX certification extends to home audio receivers, speakers, desktop systems, soundbars, acoustic materials, microphones, and HDMI cables.
THX's Select2 certification is given for home theater components said to be good enough for medium-sized rooms, up to 2,000 cubic feet (57 m3) in size, with a 10–12 feet (3.0–3.7 m) viewing distance from the screen.
I/S Plus Systems
THX's I/S Plus systems include an AV Receiver + Speaker Bundle and are certified to fill a small home theater or dorm room where the viewing distance from the screen is 6–8 feet (1.8–2.4 m). These THX certified Home theater in a box systems are so far exclusively made by Onkyo.
THX Certified Multimedia Products are designed and engineered for PC gaming and multimedia on the desktop.
The logo and the Deep Note
|This section needs additional citations for verification. (March 2014)|
THX first appeared in theaters, in which their logo would show before the start of a film. Since THX was originally created for motion picture quality, the very first film to show THX was Star Wars Episode VI: Return of the Jedi, in its theatrical debut on May 25, 1983. From there, THX began to appear before all movies from July 1, 1983, until August 30, 1997, when THX was no longer classified as a "motion picture sound system". At that point, THX had certified VHS/home video releases (as well as Laserdisc at the same time, and later DVDs, after 1998) beginning in 1995. Prior to September 1, 1997, no longer being known as a "sound system", THX was removed from all theaters, with the exception for a couple of trailers that THX had then-recently created (such as its own mascot, Tex the Robot) in 1996, would vaguely be seen in theaters. Also, in 2000, based on the long-lasting "Broadway" trailer, a new trailer called "Broadway 2000" could be seen in theaters and DVDs.
The THX trailer entitled "Cimarron" which first appeared at the start of the 1988 film Willow, used music composed by James Horner, and did not use the 'Deep Note', while "Grand", which is played in theatres from 1993 to 1997, featured a variation of the "Deep Note".
In a 1994 episode of The Simpsons entitled "Burns' Heir", a THX trailer plays before a film, literally blowing the audience out of their seats, shattering eyeglasses, teeth, and even causing one person's head to explode; the audience whoops in response. Grampa Simpson shouts, "Turn it up! Turn it up!". This segment was later turned into a THX theatrical trailer.
The "Broadway" trailer on the DVD releases has a lower-pitched Deep Note, while the VHS/Laserdisc logo has a higher-pitched Deep Note that was similar to the "Wings" logo from its theatrical debut in 1983. The Deep Note was remixed and "pitched" a number of times between its debut in 1983 and today. While the long-well known crescendo was used as well, it became shortened once THX had "graduated" to VHS/DVD/Laserdisc releases of certified features, along with the Deep Note, and its pitch. However, beginning in 2007, with the introduction of the "Amazing Life" trailer, the Deep Note was cut to just one pitch (where both synth notes are in one pitch), following a variety of instruments that shape like flowers, mushrooms and other plants playing a short tune that plays in the trailer. In the same trailer, the mushrooms make drumbeats while the flowers and other plants vibrate other musical noises. With the release of Terminator 2: Judgment Day on DVD and Blu-ray, the Deep Note was slightly remixed, which was also in the same form in the Broadway 2000 logo. When the THX Calibrator Blu-ray disc debuted, two new versions of the original Broadway trailer were released. One which is an HD restoration of the trailer, the other which is the 3D version of the trailer. 
- Crabtree, Sheigh (2002-06-12). "Lucas' THX stakes out new galaxy". The Hollywood Reporter. Archived from the original on 2002-08-11. Retrieved 2013-04-19.
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- "Self-guided tour" (PDF). Retrieved 14 January 2013.
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