Many consumers erroneously consider THX a multi-channel sound format, similar to Dolby and DTS. THX is a certification program which assures the finest picture and sound quality for cinemas, mixing studios, home cinemas, Blu-rays, multimedia products, and luxury automotive vehicles.

Absolutely! The goal of THX home cinema is to accurately recreate the experience of the film mixing studio. All mixing studios are capable of creating both 4 and 5.1 channel mixes. The acoustics, equalization curves, and loudspeaker arrays used in a mixing studio remain the same for a digital 5.1-channel soundtrack as they do for a 4-channel Dolby Surround soundtrack. THX home cinema technologies are needed to reproduce these movie soundtracks accurately.

In the beginning there was only one set of THX criteria for home cinema audio systems, simply known as THX. However Lucasfilm THX realized that its standards had to be differentiated for different size home cinema rooms. THX Select is the THX reference standard for smaller rooms. THX Select criteria are specifically calibrated to define reference level performance in room volumes of about 2000 cubic feet.

During the CES (Consumer Electronics Show) of 2007, THX announced the THX Select2 certification as an upgrade to the company's THX Select specification for home entertainment products. The new THX Select2 certification provides additional THX listening modes for enhancing playback of a variety of entertainment content, including movies and video games. It specifically addresses receivers, incorporating new features and improved noise floor performance. Based on the same values and principles of THX Ultra2, THX Select2 certified receivers deliver higher quality to smaller home cinema environments.

THX Ultra is the original THX home cinema standard. THX Ultra applies more rigorous standards to home cinema components, so that they provide the reference level performance for viewing rooms up to 3000 cubic feet.

THX Ultra2 requires amplification for seven channels and stricter requirements for amplifiers and speakers than THX Ultra (Ultra2 specification calls for a subwoofer flat to 20Hz, down from THX Ultra’s 12dB roll-off below 35Hz). The specification also features switchable Boundary Gain Compensation (BGC) that alleviates boomy bass as a result of near-wall listening positions (or, for that matter, subwoofer placement). The Ultra2 processor accommodates both 5.1 EX/ES soundtracks, as well as multi-channel audio recordings by directing ambient sounds to the dipole speakers and discrete effects/sounds to the back channels.

The THX certification for multimedia products aims at delivering cinema-quality picture and sound to the desktop by ensuring that multimedia products comply with THX’s rigorous standards. In other words, the THX certified multimedia stamp is a guarantee that your computer setup is capable of delivering the highest possible fidelity for your MP3s, CDs, DVDs, games, and other digital audio sources, through cinema-quality audio and visual experience.

Note that THX certified multimedia speakers are not to be confused with THX Select certified speakers, which offer the best quality in a home cinema setup as opposed to more modest computer designs.