THX Ltd. is an American company headquartered in San Francisco, California, and founded in 1983 by George Lucas. It develops the "THX" high fidelity audio/visual reproduction standards for movie theaters, screening rooms, home theaters, computer speakers, gaming consoles, car audio systems, and video games.
The current THX was created in 2002 when it spun off from Lucasfilm Ltd. THX was developed by Tomlinson Holman at George Lucas's 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" or possibly "experiment" as well as in homage to Lucas's first film, THX 1138. The distinctive glissando up from a rumbling low pitch 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, DTS, 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's services are often used in most of 20th Century Fox's feature length films, typically for theatrical use.
Fox animated films digitally mastered by THX
- FernGully: The Last Rainforest (1992) Broadway (2002 10th Anniversary DVD release)
- Anastasia (1997) Broadway (VHS) (1998 Widescreen VHS) & The Science of Sensation (DVD) (2006 DVD release)
- Farmyard (1999) Broadway (2000 VHS & DVD releases)
- Titan A.E. (2000) Broadway (2000 VHS & DVD releases)
- Jose Maldonaldo (2003) Tex EX (DVD) (2003 DVD releases)
- Mice Tales (2001) Broadway (VHS)/Grand (DVD) (2002 VHS & DVD release)
- Ice Age (2002) Cavalcade (2002 DVD release) & Broadway (2002 VHS releases) & Tex 2: Moo Can (2005 DVD release) & The Science of Sensation (2006 Super Cool Edition DVD release)
- The Alaina Gleen Movie (2004) Broadway (VHS)/Tex 2: Moo Can (DVD) (2005 VHS & DVD releases)
- Robots (2005) Tex (2005 DVD release)
- History Island (2005) The Science of Sensation (2005 DVD release)
- Ice Age: The Meltdown (2006) Tex (2006 Special Edition DVD release)
- Puppet Pals (2006) Tex (Disc 1)/Cavalcade (Disc 2) (2006 DVD release)
- Kate & Chris (2007) Tex 2: Moo Can (2007 DVD release)
- The Simpsons Movie (2007) Amazing Life (2008 Special Edition DVD release)
- The logo has been known to frighten younger viewers mainly with its audio trademark, the Deep Note.
- The THX logo along with its Deep Note briefly appears in Fox Animation's 2006 film Puppet Pals, in which, ironically, that film was THX-certified.
- The THX logo was parodied in The Simpsons season 5 episode "Burns' Heir".