THX, the trademark of THX Ltd., is the ultimate set of standards for home theatre sound. It incorporates a series of patented electronic and loudspeaker specifications designed to bring the big theatre experience right into your home.

THX Certified Home Theatre products deliver cinema-quality picture and Hi-end sound to home environments. Through optimized audio-visual technology and speaker placement, you get a movie experience at home that's as faithful as possible to what the director intended.

Products certified by THX assure the best possible quality in music and sound reproduction.

THX Certification is the “seal of approval” for speaker quality. It is the absolute assurance that your loudspeakers will reproduce all music and film material in the way that the composer and film director respectively intended.

THX Ltd. is the founder of quality assurance programs for superior cinema presentation and the leading provider of product certification and venue design for the entertainment and consumer electronics industries.

To ensure accurate playback as the director or the producer intented.

The digital sound formats were developed for movie presentation in cinema settings. Because home environments are different to cinemas, the same THX audio standards that ensure accurate playback in theatres have been adapted for viewing movies in Blu-ray, DVD and broadcast formats at home.

Incorporating a variety of digital encoding technologies like Dolby Digital, DTS and PCM, THX Certified Home Theater products offer the most consistently accurate, trouble-free reproduction of sound. THX certified equipment offer comprehensive solutions to multichannel audio formats based on their end to end home entertainment expertise. THX certified equipment ensure:

- Very clear dialogue
- Sharply positioned sounds
- Enveloping surround sound that puts the audience inside a movie
- Thunderous bass and crystal clear highs
- Maximum contrast between quiet and loud sounds
- Smooth and continuous sound movement

THX Certification has nothing to do with the type or format of the sound information stored in the CD, Blu-ray or DVD. The high standards of a THX certified speaker determine its capability of reproducing crystal clear sound and music. In this way a THX certified loudspeaker has the same perfect behavior in any input signal.

Each THX home cinema component - processor, centre speaker, surround speaker, subwoofer, amplifier, Blu-ray player, interconnect, speaker wire, and acoustically transparent screen - solves specific problems in home cinema sound reproduction. You can use any THX home cinema product in any home cinema system. When used all together, these components work synergistically to produce an ultimate surround sound experience.

The driving force behind the establishment of THX certification was the observation that conventional audio components could not accurately reproduce film soundtracks in the home environment.

A need to correct the audible tonal and spatial errors caused by the playback of soundtracks designed in and for large cinema in the smaller environment of a home. A need to more accurately reproduce the complex and competing sound fields present in multi-channel sound playback.

Movie cinema THX certification was introduced in 1983. THX certification was developed by director George Lucas, who was dismayed with the sound quality of most cinemas. He felt that all of the directors’ efforts to stir the emotions of the audience with the use of sound and music were undermined by poorly equipped cinemas that reproduced highly distorted sound. George Lucas tasked Tomlinson Holman (then his corporate Technical Director) to develop a set of criteria that cinemas had to meet to guarantee that the soundtrack was played back just as the director intended. These criteria were named Tomlinson Holman eXperiment, or THX for short.

The home version of THX was introduced to the public in 1990. Home THX certification aims to duplicate the THX cinema sound in a home environment. The THX home cinema standard has a firm foundation in the production processes associated with all feature film material.

The THX standards are a set of minimum criteria that audio components must meet. In addition, there are many different types and levels of THX certification that components can obtain. Manufacturers of home cinema components can differentiate their products by outperforming the minimum standards specified by each certification level and therefore produce components that do not sound alike.

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.

Yes. The speakers in a THX home cinema system (both Ultra2 and Select) are optimized for multi-channel sound (4 or 5.1 channels), so you get better imaging and clarity from the front speakers, and more envelopment from the surround speakers. Both of these benefits are ideal for music reproduction.

The difficulty exists because dialogue in a film competes with music and sound effects. In addition, all of the sounds are coming at the listener from many different directions. Clearly, the best way to hear clean dialogue is to reproduce it with as little coloration as possible. This means you need to hear flat frequency response all across the listening area and have controlled speaker/room interaction.

THX home cinema 5.1 systems include three front speakers (left, centre and right), two surround speakers and one or more subwoofers. Many systems also include one (6.1) or two (7.1) more surround back speakers. Each speaker has its own specifications and characteristics although a flat frequency response in the range each speaker is called to perform, is a prerequisite.

The final requirement for accurate multi-channel sound reproduction is accurate deep bass response. All THX subwoofers are designed to precisely match left, centre, and right (LCR) speakers through the electronic crossover in a home THX processor or receiver. THX subwoofers must have an accurate in-room response from 35Hz to 200Hz so that the crossover at 80Hz results in a smooth transition. Approved systems must be able to generate 102dB sound pressure level or louder without distortion in a listening room of 2000 cubic feet (roughly equivalent to a 20 square metre room).

Conventional two-channel speaker designs are constructed to present a good solid image over a 45 to 60 degree angle. If you spread the speakers too far apart, you get a hole in the centre image. Place them too close together, and the soundstage collapses into a fuzzy mono sound. In a multi-channel sound system, sound images are formed between left and centre and right and centre speakers. This means that speakers must be more precise in their imaging characteristics.

Front channel imaging is extremely important in producing accurate sound. For films, the sound has to match the picture perfectly. Home THX front channel speakers improve dialogue intelligibility and imaging in two ways. First, they provide wide horizontal dispersion. This allows for people sitting off-axis to hear full and flat frequency response. The second technique is to control the speakers' vertical dispersion. Audio engineers have found that the ceiling and floor reflections deteriorate a speaker's ability to image. In addition, the coloration from these vertical reflections cloud intelligibility.

Few enthusiasts realize that the centre speaker handles almost 40% of the dialogue in a typical surround presentation! Our ‘Free Air’ spherical rotating tweeters and THX certified dispersion characteristics ensures you'll never miss a word of dialogue.

THX recommends that the surround speakers are dipolar, which are designed to provide a "movie without walls" experience. A dipolar speaker does this by painting the walls and the ceiling with sound. It sends very little sound towards the listener. The sound reflecting off the room’s walls and ceiling provides an enveloping soundfield, immersing the listener in the movie experience.

The total energy radiated by a speaker in all directions is called its "Power Response". The THX dipolar surround speaker is required to have a flat power response. This means that the total energy radiated by the speaker (in front, above, below, behind, and to the sides) must together average a flat frequency response. With the total speaker energy being flat, a listener anywhere within the surround speaker's firing area will hear flat frequency response.

In a cinema, the surround speakers and the front speakers are different because they do different jobs. The front speakers deliver clear dialogue and localized sound that matches the picture. The surround speakers create diffuse and enveloping surround ambiences with occasional effects like pans or "fly-overs." If you build a 5.1 channel home cinema system using conventional loudspeakers, you’ll need a minimum of five matched speakers plus a subwoofer for accurate sound reproduction. By contrast, THX home cinema speakers have multi-channel sound capabilities built in. THX LCR speakers and THX dipole surround designs psycho-acoustically match the best surround sound performance of a cinema or mixing stage. The THX subwoofer keeps the size of all of the speakers small while allowing for peak dynamic range and bass performance.

THX recommends the use of main L/R front speakers that handle bass frequencies down to 80Hz, with one or more subwoofers for frequencies below. When using smaller loudspeakers we can cut off the bass at 120Hz instead of the optimum 80Hz crossover point. The associated subwoofer crossover frequency must also be adjusted to handle frequencies up to 120Hz. And we make that easy because all our THX Select certified subwoofers faithfully reproduce the bass up to 200Hz! Crystal has you covered!

The Re-Equalization circuit found in THX processors, corrects the over-bright sound of movie soundtracks. Movies are mixed in cinemas with a controlled high frequency roll-off, called the "X-Curve". This curve, an international standard, is part of every mixing and cinema's playback system because high frequency roll-off is appropriate for sound sources that are not close. But since home listening distances are shorter, audio mixed under the "X-Curve" sounds too bright when played back through flat response speakers. To match sound for smaller spaces and distances, THX uses a special Re-Equalization Curve, designed for home environments, to restore the correct tonal balance of a movie soundtrack.

* Image explaining this THX technology belongs to THX Ltd

Adaptive Decorrelation compensates for monophonic surround channels in Dolby Pro Logic. In the cinema, this goes unnoticed since the sound is mixed up by the large number of surround speakers and by small room reflections. Your left ear and right ear never get identical sounds, so you never identify the surround sounds as mono. (Even with Dolby Digital and DTS sound and "split" left/right surround channels, mixers use a lot of mono surround sound effects.)

In a home environment, you’d detect the mono "feel" of the surround channels. In response, the THX Decorrelation Circuit subtly adjusts the time and phase of one surround channel against the other. This constantly changing time and phase differences means that your left ear and right ear never hear identical signals. The sound is never identified as mono and remains spacious, just like in the cinema. For Dolby Digital and DTS split surround signals, an intelligent Adaptive De-correlation circuit de-correlates the surround channels only when it senses mono surround signals.

* Image explaining this THX technology belongs to THX Ltd

THX Loudness Plus is a new volume control technology with which home cinema audiences can now experience the rich details and ambient sound in a surround mix at any volume level. THX Loudness Plus incorporates two new THX technologies. As you change the volume, THX Multi-channel Spectral Balancingâ„¢ and THX Dynamic Ambience Preservationâ„¢ automatically and seamlessly apply the appropriate compensation. This delivers a more accurate listening experience at any volume level.

Basically, what it does is to automatically adjust the front-to-back speaker level relationship as you turn the volume level down so that the perceived sounds match as closely as possible the original mix as played back at the reference level (as was recorded and mixed in the studio).

THX Advanced Speaker Array (ASA) recreates the 5.1 studio surround sound field in your home by digitally reconfiguring the surround channels for the type of media you are enjoying. Featured on all Certified Receivers, THX ASA establishes THX Listening Modes, making it convenient to have one speaker set up for movies, music and games. 

	THX Cinema Mode Recreates the ambiance of the movie theater by positioning the 5.1 mix to immerse you in the movie’s soundtrack.
	THX Games Mode Distributes the sound effects and dialogue generated by the game engine, placing the audio from a 5.1 mix source to the appropriate “action” location – creating 360-degree gaming experience.
	THX Music Mode Emulates the original studio environment by repositioning the 5.1 surround sound mix further behind you for an accurate and increased sense of spaciousness and localization – placing you directly in the recording session.

THX Surround EX

Decodes the third surround channel from the traditional two surround channels, creating a more immersive entertainment experience. 

* Images explaining these THX technologies belong to THX Ltd