THX
THX is an American company in the field of sound and image reproduction. It was founded in 1983 by George Lucas and is based in San Francisco .
The company is known for its quality seal of the same name for cinemas , home theaters , computer speakers , game consoles and car hi-fi systems.
Companies
The company THX Ltd. was founded in 1983 by George Lucas as a certification body for cinemas. The driving force was Tomlinson Holman , who, during his work as a sound engineer, found time and again that the film sound that he had mixed in the studio often did not arrive in the cinema in the same form .
The origin of the name is unclear. Three possible explanations are:
- " T omlinson H Olman e x periment"
- "Tomlinson Holman Crossover", based on the THX Ltd. manufactured crossover network (THX monitor).
- " THX 1138 ", based on Lucas' first movie.
Holman developed a system of standards that unified the acoustics from the recording studio to the cinema. Not only the technology used must be subject to these standards, but also the rooms, as their properties have a decisive influence on the perception of sounds.
The obvious reference for Holman's norms was a movie theater in Hollywood showing films for the Academy Awards.
THX is just a standard for perception; The means by which sound (and image) are reproduced is completely irrelevant for THX, as long as the result corresponds to the THX standard.
Accordingly, THX does not sell any devices. The THX Monitor (currently the THX Monitor D1138), essentially a crossover and monitoring amplifier, is part of the THX Ltd. granted license and property of THX Ltd. This crossover is adjusted by a THX technician, depending on the built-in, THX-certified speakers. Then, with the help of the equalizer in the cinema processor, the playback is adapted to the applicable standards. After installation, the demonstrator can listen to the sound on all channels (individually or as a sum) in front of and behind the power amplifiers in order to check whether they are all working properly during operation.
In October 2016, THX was acquired by computer accessories manufacturer Razer .
Seal of quality THX
Today's meaning
According to the THX standards currently in force, extensive requirements apply to cinema halls, which not only affect the sound but also the picture, as well as external influences (e.g. the noises from the air conditioning system). THX Ltd. not only certifies technical devices and checks existing cinemas, but also offers consulting services for new buildings.
If a cinema meets all the requirements, it will receive it on request (and against payment) from THX Ltd. a THX license, compliance with which is checked annually even after it has been awarded.
In March 2008, according to THX.com, over 2000 cinemas in over 30 countries were THX certified. In June 2007 the website also showed over 2000 movie theaters.
Distribution in German cinemas
THX is becoming less and less important in the German cinema market. Since 2003/2004, for example, the Cinemaxx chain has no longer had any certificates for its halls because, for reasons of cost, they signed the contracts with THX Ltd. quit.
In May 2014 there were 19 THX-certified cinemas in Germany.
For comparison:
- March 2006: 44 certified cinemas
- June 2006: 40 certified cinemas
- January 2007: 35 certified cinemas
- April 2007: 32 certified cinemas
- June 2007: 31 certified cinemas
- August 2007: 26 certified cinemas
- December 2007: 22 certified cinemas
- February 2008: 20 certified cinemas
- April 2008: 23 certified cinemas
- June 2008: 23 certified cinemas
- March 2009: 20 certified cinemas
- May 2014: 19 certified cinemas
(Source: accessed in the corresponding month)
The main cause is the uncertain relationship between the high license costs on the one hand, which are difficult to cope with in times of declining visitor numbers for the cinemas, and the difficult to determine THX advertising effect for the cinema on the other.
THX Ltd. itself issues a large number of licenses in the Home THX area ( e.g. for sound cards , DVD or VHS cassettes). At least for parts of the cinema industry, this inflationary appearance of THX seals in everyday life is not a convincing strategy to exclusively award the highest quality. In addition, there is sometimes a lack of control over the conditions for a theater license and the use of THX trailers (THX advertising films placed before the main program) in halls that are not THX certified, which means that the “THX experience” is not always available meets the promised high standards. Complaints from the public about a toll-free number (as in the USA) directly to THX Ltd. judging is not possible in Germany.
Furthermore, parts of the cinema industry argue that THX no longer brings any advantages since the digital recording of cinema sound ( dts , SDDS , Dolby Digital ). It is generally assumed that digital recording, in conjunction with the technical possibilities in newer cinemas, has actually brought about a quality improvement. However, the digital recording does not determine how the viewer perceives the sound. An optimally mixed, high-quality digital sound can only be poorly reproduced in cinemas with inferior components or poor acoustics.
In many cinemas, especially in the multiplex cinemas , THX-licensed components are still installed, because their quality is undisputed. As in the Cinemaxx example above, the aim is to save the costs for the mandatory annual inspection and the associated annual recertification of the cinema as a whole. Without a certification by THX Ltd. the use of the THX monitor , the essential component, is not possible. The THX monitor is provided by THX Ltd. not sold, but part of the license.
THX outside of the cinema
Since the advent of the home cinema market, THX seals have also been available for this area in the THX Select 1 and 2, THX Ultra 1 and 2 and THX Certified Multimedia variations . All devices, from amplifiers and speakers to sound cards, are certified .
THX-Ultra represents an increase over THX-Select. THX often uses the room size as a benchmark. As a result, a THX-Ultra certified device (such as a loudspeaker) must do at least the same as a THX-Select device in a smaller room.
In addition, special regulations apply to certification for certain device groups:
With THX-certified amplifiers and preamplifiers, various electronic circuits and equalizer programs are also prescribed, which are intended to achieve a sound improvement in the sense of THX. As an example, speaker systems with dipole speakers (radiating in two directions - one of which is out of phase) are mentioned, which, however, are not provided for in all THX standards.
THX Select
Since the requirements for THX Ultra can hardly be met by any home theater system, THX Select is mostly used in the home.
The THX circuit includes the following functions:
- Re-equalization
The original soundtrack is designed for playback in large cinemas with special sound requirements. The loudspeakers are positioned far in front of the audience or behind the screen. In order to ensure good speech intelligibility in the last row, the high frequencies must be reproduced louder than the bass. If this soundtrack is played back on a home theater system, the result would be a too bright, unnatural sound image due to overemphasis on the mid and high range. The treble boost is compensated for by re-equalization. Music and speech are reproduced naturally and realistically.
- Timbre matching
In the cinema, surround effects are implemented using a large number of loudspeakers in order to ensure the most realistic sound possible without sound holes. The sound of all speakers used must match each other. In the home theater, however, there are only two, at best four, surround speakers, the sound of which is matched to the sound of the three front speakers by means of the timbre matching.
- Decorrelation
Dolby Pro Logic works with three front speakers and a mono effects channel which is transmitted by two speakers. THX uses decorrelation to improve the impression that the effects are not emitted by two loudspeakers, but rather come from the room so that the viewer cannot locate them. Here, the mono channel is split into two channels whose frequency and phase position differ from each other just enough that they are perceived as different.
The digital technology adds two additional functions:
- Bass peak management
The loudest part of a film soundtrack is the bass component, which is output to the subwoofer connected via the LFE (Low Frequency Effects) channel. Due to the extremely dynamic nature of a Dolby Digital soundtrack, the subwoofer may have to transmit signals that exceed its capabilities. The result would be considerable sound effects through distortion and penetration of the bass system. Bass peak management limits the bass signal to a peak value so that the subwoofer's performance profile is not exceeded.
- Loudspeaker Position Time Synchronization
Ideally, all loudspeakers in a multi-channel system are at the same distance from the listening position, but this usually looks different in practice. Loudspeaker Position Time Synchronization compensates for these differences by digitally setting the delay time of each individual speaker to the listening position.
- Loudness Plus
The Loudness Plus function ensures that films sound almost the same as in the cinema, even if the playback volume is below the reference mix level, as the reference volume is not recommended for most living rooms in relation to the size of a cinema room. An example would be the playback of a movie in the living room from a Blu-ray Disc that was mixed with sound for a movie theater. Playing back the movie soundtrack with the reference level intended for the cinema hall during the presentation, and due to the high dynamic range of the recording, would result in extremely high sound pressures in the living room (in the worst case up to 120 dB (C)) because of the small room size, in which the sound pressure cannot be distributed, but rather multiplies even in extreme cases at the listening position due to sound reflection on walls, room resonance and wave superimposition . Playing the recording below the reference level at low volume would lead to a loss of dynamics in order to compensate for this and to maintain the dynamic range at low sound pressure levels and to come closest to the acoustic impression of the original, volume compensation is required.
In addition to THX SELECT for home cinema systems in smaller living spaces, there has been a THX ULTRA for high-end components since 1999 , which was replaced in 2002 by the broader THX ULTRA 2 standard . In the case of loudspeakers, THX Ultra 2 has a wider dispersion in the vertical direction and improved high-frequency reproduction, which should primarily lead to a higher "musicality" of the loudspeakers (but also aroused slight skepticism in the scene because some of them suffered slight losses in film sound reproduction compared to THX Ultra feared). For amplifiers and receivers, Ultra 2 includes, in addition to the mandatory number of 7.1 channels and THX Surround EX, the "Adaptive Speaker Array" (ASA) DSP circuit, which enables the two "Back Surround" speakers to be set up more variably, which is also no longer of a dipolar nature may be. In the case of the subwoofer, the "Boundary Gain Compensation" was added, which is used to cut the lowest frequencies during playback when activated and thus counteract any excessive subwoofer droning near walls. Ultimately, both THX Select 2 and Ultra-2-certified amplifiers and receivers offer various THX playback modes that serve the purpose of adapting the sound impression adequately to the corresponding source material (films, music, games) on the one hand, and 5.1 material acoustically correctly on the other hand Split 7.1 speaker layout. The playback modes in detail are:
- THX Games Mode (re-equalization switched off, side and back surrounds are switched acoustically in parallel, with a slight focus on the side surrounds - ideal for video games in 5.1 format)
- THX Music Mode (re-equalization switched off, side and back surrounds are switched acoustically in parallel in order to generate a phantom sound source between them and thus simulate a setup of 5 identical speakers - ideal for music in 5.1 format)
- THX Ultra 2 Cinema (re-equalization switched on, side and back surrounds are switched acoustically in parallel, with a slight focus on the side surrounds. This creates the sound impression of a large cinema hall with L-shaped side and rear speaker arrays on the right and left side - ideal for films in 5.1 format)
- THX Surround EX (re-equalization switched on, an additional rear center channel is extracted from the two rear channels of the 5.1 signal (which are reproduced via the respective side surrounds) using an analog matrix circuit, which is distributed equally to the In this way, film soundtracks are reproduced using the so-called "Matrix 5.1" (also "Matrix 6.1") method.)
Individual evidence
- ↑ Razer takes over audio specialist THX. pcgameshardware.de, October 18, 2016, accessed October 18, 2016 .
- ↑ a b www.thx.com , accessed June 2007
- ↑ Current list of components approved for cinemas (English) ( Memento of the original from August 2, 2010 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
Web links
- Official website (English)
- Cinefreaks - THX (obsolete)