THX (Tomlinson Holman Experiment) is a set of technical standards developed by Lucasfilm to ensure that moviegoers see and hear a film at optimum performance levels, as the director intended. This comprehensive set of standards includes rigorous specifications designed to optimize equipment, room acoustics, background noise levels, and projection and viewing angles. Think of THX as the auditorium itself. The THX Sound System was developed in 1982 during the production of Return of the Jedi.
Inspired by George Lucas' interest in upgrading film presentation standards in the industry, Lucasfilm's Corporate Technical Director, Tomlinson Holman, began to identify problems related to theatre sound. Holman noted theatre audiences were not hearing what was recorded in the film studio - many of the subtle sounds were missing. His innovative approach was to consolidate existing performance standards into a new system which included theatre acoustics as well as sound equipment.
THX (named after Lucas' first feature film, THX 1138) is a sound system designed specifically to reproduce film sound exactly as it was recorded by the filmmaker. The THX Sound System is the only program of its kind to consider all aspects of a theatre's audio and visual performance, including architecture, acoustics and equipment. "THX is really a performance criteria; it's not a specific set of components," says Holman. The system was created to complement advances made by Dolby Laboratories in decoding sounds in the sound track which concentrates on the "A-Chain." The THX Sound System concentrates on the "B-Chain" of a theatre's sound system. The "B-Chain" is comprised of customized acoustical design work for each auditorium, a special screen speaker installation method, a proprietary electronic crossover network, and rigorous audio equipment specifications and performance standards.
Upon completion of a THX Sound System installation, the theatre is tested by a THX engineer to make sure it meets both THX environmental technical criteria and recommended industry standards for high quality visual and sound presentation. Theatres are recertified to ensure that optimum quality is maintained. A certified THX theatre carries several important advantages for the movie-goer. The audience enjoys a more naturally balanced sound that uniformly reaches every seat in the auditorium, improved dialog intelligibility and decreased bass distortion. Better stereo localization makes the sound appear to travel across the screen with action. A frequency range that is wider by a full octave in both bass and treble allows patrons to hear higher highs and lower lows. The combined result is the reproduction of the same clear, dynamic sound originally created by the filmmaker.
Home THX Audio Systems, developed by George Lucas' THX Division, have become the world's standard for film enjoyment in the home. For over 15 years, THX has licensed its patented technology to leading A/V and PC manufacturers worldwide. The legendary training program has certified more than 1300 dealers as among the highest qualified to sell and install Home THX products. THX also certifies home video software through the THX Digital Mastering Program, ensuring that DVD software, laser discs and VHS videotapes provide the best image and sound quality possible through the use of patented THX technology and our unique quality control expertise.
THX Certification Levels:
THX Select
THX Select designates home theater components that meet most of THX Ultra´s requirements, but have been given more flexibility in terms of size and design. These systems are best suited to smaller rooms and allow for easier placement. THX processing remains the same and the ability to achieve 105dB sound levels is also the same.Certification program for speakers and receivers that assures a base level of quality and performance when played in a room that's between 2,000 and 3,000 cubic feet.
THX Select2
THX Select2 Certified Products are engineered and designed for small to medium sized home theaters. Viewing distance of approximately 10 feet / 3 meters from the display to the listening position
THX Ultra
Certification program for speakers, receivers, and amplifiers that assures a base level of quality and performance when played in a room that's greater than 3,000 cubic feet.
THX Ultra 2
The newest certification from THX, THX Ultra 2 requires amplification for seven channels, boundary compensation for subwoofers, and stricter requirements for amplifiers and speakers than THX Ultra. Dipole speakers are used for the side surround channels. Monopole speakers are used for the surround back channel and are placed next to each other. The Ultra 2 processor accommodates both 5.1 EX/ES soundtracks, as well as multichannel audio recordings by directing ambient sounds to the dipole speakers and discrete effects/sounds to the back channels.
