The THX trailer that precedes compliant films is based on the Deep Note, with a distinctive glissando up from a rumbling low pitch.

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.

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").

[5] Under Creative Technology, the company developed several further innovations, such as the first THX-certified audio card for computers, the Sound Blaster Audigy 2.

Using an intricate crossover network that integrated equipment with the room's unique acoustics, it was observed to be the highest quality theater sound system in existence.

Five games by Electronic Arts, including Need for Speed: Underground, Medal of Honor: Rising Sun and The Lord of the Rings: The Return of the King carried logos on their box and pre-game trailers.

[18] In 2020, THX Certified Game Mode was introduced, with enhanced contrast and color, and reduced input lag, and greater accuracy to the producers' intentions.

[19][20] It has judder and smear reduction, meaning that the picture remained crisp with a quick rise time between dark-to-light transitions.

To earn the new THX 3D Display Certification, the PX950 passed more than 400 laboratory tests evaluating left and right eye images for color accuracy, cross-talk, viewing angles, and video processing performance.

These auditoriums featured THX Certification, patented deep curved screens, 65-channel Dolby Atmos immersive surround sound and the first 4K laser projector in the United States.

These auditoriums featured large wall-to-wall screens, 2D and 3D digital projection, immersive, surround sound, premium seats with Luxury Lounger electric recliners, and THX Certification.

This theater provided exhibitors with a branded and differentiated PLF offering that included projection technology from Cinionic, and an immersive audio system, acoustics, and auditorium specifications that met THX certification standards.

[35] In September 2020, Walmart stores began to sell Gateway laptops and tablets, which were tuned by THX, ensuring brighter contrast with more rich vibrant screen colors.

The laptops featured THX Spatial Audio that delivered an authentic 7.1 surround experience through built-in speakers and attached headphones.

[37] The first THX theater is the University of Southern California's Eileen L. Norris Cinema Theatre, a part of USC's film school.

THX certification extends to home audio receivers, speakers, desktop systems, soundbars, acoustic materials, microphones, and HDMI cables.

[39] THX Certified Ultra products are for larger home theaters, 3,000 cu ft (85 m3) in size, with a viewing distance of 12 foot (3.7 m) or greater from the screen.

THX Certified Select products are for medium-sized rooms, up to 2,000 cu ft (57 m3) in size, with a 10–12 foot (3.0–3.7 m) viewing distance from the screen.

THX Certified Dominus products are for expansive home theater spaces, 6,500 cu ft (180 m3) in size, with a 20 foot (6.1 m) viewing distance from the screen.

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).