WTF Is A THX Certified Display?

May 4th, 2010 · 26 Comments · Front Projection, LCD Flat Panel, LED LCD Flat Panels, News, Plasma

THX Certified Display-bw 425

(May 4, 2010) Director George Lucus created the THX Certification program in 1983 to institute audio and film reproduction standards for movie theaters. Later, THX began an audio certification program for home theater. More recently, THX introduced new standards for home HDTV certification (for more on THX history click this link). To receive THX certification a display must pass a battery of tests incorporating over 400 data points.

THX chose the HD Guru as the first journalist to reveal details about its display testing program. (Disclosure: THX paid expenses to visit its San Rafael headquarters)

Our host provided a complete copy of its requirements and specifications for certification with the understanding (for competitive and business reasons) we would only publish the list of test categories with a limited number of the exact specifications. We jumped on the chance to pierce the armor of secrecy surrounding THX’s video standards.

THX Circle Zone Plates 425

Inside THX’s test lab, we observed their array of test signals and procedures. In addition to the legacy test signals we and other reviewers use to evaluate HDTVs, THX created some of their own patterns (see photos).

THX tests signal processing, deinterlacing, color points, black levels and white levels among others criteria. They perform additional testing of display properties that are generally too time consuming or require special test equipment the HD Guru and our fellow reviewers don’t possess. Here is a link to a never before released list of THX tests.

THX Test Equip. 425THX Testing Lab 1 425

The Secret Sauce

Below, the techies among our readers can see the seven of the dozens of specifications a display must meet for THX Certification. These tolerances are quite tight.

A brief explanation of the seven items

1) Primary and secondary color points must be within a±0.005 variation.  2) Low panel reflectance allows viewing in an environment with lamps. Please note no anti reflective filter is 100% effective.  3) Uniformity assures no dark or light areas on the panel, a problem that plagues many LCD (and LED-LCD) panels. 4) Off axis color accuracy assures minimal color shift as one moves up to 45º off center, another common issue with many LCD panels. 5) Tests for residual images (called image retention) on a plasma display. 6) Confirms display of 100% of the image, assuring no aliasing artifacts with 1080i/1080p content. 7) Assures the signal processing within the display provides full resolution without adding undesirable artifacts.

THX provided the following italicized section:

The items below are a snapshot of some of requirements to achieve THX Display Certification. The test sample provided by the manufacturer must meet or exceed all THX requirements, as listed in the THX specification, when measured in our San Rafael facility. All requirements pertain to the THX picture mode; the manufacturer may choose different settings in other picture modes.

  1. 1. Rec. 709 Standard. THX restricts the color gamut to Rec. 709 as all source material is mastered to these limits. The display must measure within ±0.005 of the coordinates listed below for white, red, blue and ±0.010 for green coordinates (Sec. 3.1.5)
Color Rec. 709 Chromaticity**
x y























  1. 2. Panel Reflectance. THX requires a panel reflectance of <2% to ensure good contrast in a moderately lit viewing environment, which keeps the image dark the presence of  lamps. (Sec. 3.1.12)


  1. 3. Uniformity. THX measures the uniformity by comparing eight locations at the edge of the panel to the center. THX mandates that black and white panel uniformity must be >80% in luminance and within ±0.004 in color. (Sec. 3.3)


  1. 4. Four-point viewing angle (LCD flat panel). THX compares the color and uniformity at 45º to the on-axis (90º) measurements for a color of ±0.004 and uniformity >75%. (Sec. 3.3.5)


  1. 5. Image Retention Recovery (Plasma panel). THX ensures that the image recovery utility within the panel eliminates image retention. A static checkerboard pattern is displayed for two hours. The retained image must recover >98% within ten minutes. (Sec. 3.3.7)


  1. 6. Overscan. The native 1920 x 1080 source must be presented pixel-for-pixel with no overscan. This ensures that no scaling artifacts are added to the image. (Sec. 4.2.4)


  1. 7. Video Processing. THX uses proprietary patterns to evaluate the following: judder, deinterlacing, bob and weave switching time, contouring; jaggies (smoothing), etc. (Sec. 4.0)


The requirements described and others within the THX Display Specification are incorporated in the THX picture mode. In addition, THX engineers choose the default settings of the manufacturer-specific features (noise reduction, interpolation, contrast enhancement, etc.).


THX Mode

In addition to the performance testing, THX requires implementation of a THX Movie Mode, with performance characteristics determined by THX after the display is completely characterized.

The THX Movie Mode has specific settings for gamma, color point, luminance, overscan, and other settings specific to the certified display. This setting is intended to provide the optimum settings for playback of movie titles, but can be used for viewing other content as well.


THX Jaggies 425

What Does THX Do For You?

THX certification assures buyers a high quality high definition display. TV makers can’t pass the rigid specifications by using low quality LCD or plasma panels and/or mediocre signal processors.

Engaging the THX mode assures HDTV purchasers a simple “out of the box” setting that is as accurate as you will find, without any other adjustments or extra cost post setup calibration.

We’ve tested THX Certified modes in various brand sets and confirmed they measure close to industry image setting standards. While it’s possible that an HDTV manufacturer can do their homework and produce a factory setting that provides the best possible picture quality, to date no vendor does. THX certification is available on select LG LED LCDs including the 47LE8500], and LG plasmas :50PK750, and 60PK750, Panasonic plasmasTC-P42G25, TC-P46G25, TC-P50G25, TC-P54G25, Epson front projectors, Runco front projectors and JVC front projectors. Here is a link to all the 2010 THX Certified models.

Bottom Line

If you want an accurate HDTV image, choosing a THX Certified display will get you a top quality unit without fuss. THX Certified displays continue to receive some of the highest ratings from the leading magazine and web HDTV reviewers.

Edited By Michael Fremer

Have a question for the HD Guru?

Copyright ©2010 HD Guru Inc. All rights reserved. HDGURU is a registered trademark. The content and photos within may not be distributed electronically or copied mechanically without specific written permission. The content within is based upon information provided to the editor, which is believed to be reliable. Data within is subject to change. HD GURU is not responsible for errors or omissions.


26 Comments so far ↓

  • Jacelyn Pietz

    You made some respectable points there. I looked on the internet for the issue and found most individuals will associate with together with your website.

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  • paul johnson

    in my experience as a professional calibrator, i have found the panasonic plasma TVs, and the new LG plasma TVs with THX mode, are able to produce a fantastic picture when calibrated. better than most other TVs when calibrated. the bottom line is EVERY TV needs to be professionally calibrated in order to produce the best picture. if it is not done by a professional, with a computer and pattern generator, then it is not going to be as good as it can be. most customers are not interested in some of the additional test parameters, they just want, and know a good picture when they see it. before and after calibration.

  • Consumer Advocate

    ThX is admired for the work they have done in improving consumers home theater experience.
    I do NOT admire the industry’s bogus Energy Star ratings program which even the government admits the certifications are falsified. Companies claim they meet the standards, but in independent testing indicate otherwise. So while our government and Wall Street are corrupted by lobbying and payoffs, Thx is the exception.

    There is proof that THX works behind the scenes to improve products. After a few years, Thx licensee LG displays are now surpassing Samsung (who focus has shifted from performance to profitability).

    Lastly I resent manufactures and calibrations locking-up the display’s best performance MODE. It’s ridiculous that consumers have to pay another $450, and be mislead by attributing the increased performance solely to the ISF calibration.
    THX takes the high-road and enables the service/calibration controls. Their goal is for the factory to optimize the calibration settings, so aftermarket calibration is not needed or desired. It’s taking time but progress is being made. Keep up the good work guys!

    Over at AVS forum, calibrator Chad B is trustworthy, accurate and reliable. So too is CNet with Consumer Reports improving. This year some of the highest rated displays have (largely) phenomenal performance yet are bargain priced (think LG).

  • Steve

    Only a fool would think THX would remove certification and denounce Panasonic upon discovering a thread at AVS. I imagine detailed testing must be done and perhaps additional testing methods put in place for future displays. No way THX knew about the MLL rise when they did certification…it’s not something you would have been expecting until now.
    Jeez, keep it real.

  • Greg

    So, any comment about the relatively well documented and openly admitted to increasing black level Panasonic plasmas suffer from and the floating black issue people are reporting on the 2010 models alongside the increasing black levels?

    Personally, if I was THX I would be thinking about legal action against these companies or removing the THX certification if they were ruining my company’s reputation and I was not at fault.

    If consumers stop trusting THX there will be less of a reason for companies to get THX certified, but at the same time if you start holding companies accountable to these strict standards they’ll probably decide it is too much of a hassle/risk to get certified.

  • Graham McKenna

    Hi Greg,
    My apologies to you and Mr. Stone for not addressing the question about the specific plasma review in my last post. Yes, we are evaluating the data and reviewer comments from this review, as we do with all product reviews.

    Do you own this TV? If so, we encourage you and other owners of this specific model to send us feedback to [email protected]

    Graham McKenna
    THX Ltd.

  • Greg

    Mr. McKenna is proof enough of how poor THX is nowadays. Do not get me wrong. He is very pleasant and hasn’t attacked anyone.

    When someone asks a direct question about how specific products are coming out and getting poor reviews with THX certification and all but one is clearly ignored you know they are afraid to answer truthfully to the public for whatever reason.

  • Graham McKenna (THX response)

    Mr. Stone,
    Thanks for your follow-up. THX has always reserved the right to keep its processes and specs confidential. However, we are looking at ways to make what we do more open to the public.

    Drop us a note prior to CEDIA or CES so we can arrange a time to chat. You can reach me at [email protected].

    Graham McKenna
    THX Ltd.

  • Bob Stone

    Mr. McKenna:

    Thank you for your kind response.

    The fact that THX does not certify multi-channel analog audio outputs, if nothing else, is a welcome and quite recent clarification of the THX blu-ray certification process. Regretably no one knew this until the Lexicon debacle.

    THX specs are, in fact, extremely vague. We only have your company’s (THX) assurances that detailed specs exist but can’t be shared due to their propriatary nature. In essence, THX says to the consumer – “trust us” while being paid by the manufacturer for the certification.

    Much of my prior post asked you to document how many THX products you purchased in the open market to verify compliance. You failed to respond! I am unaware of any stated THX policy in this regard. Would you kindly clarify THX’s policy regarding open market testing and how many samples of every THX certified product you test which are purchased in the open market.

    Finally you state that THX certified products are among the best reviewed products in the marketplace. Looking at the CNET review, which is only a few days ago of the LG 50PK750, we have decoder issues resulting in ringing and strange artifacts, poor performance in a lit room, and poor gamma in THX mode. Can you explain that to me.

    I very well may take you up on your kind invitation to discuss this further with you at the next conference.

    But first and foremost – please explain, for the record, your open market testing program of THX certified products.

    My thanks.

  • Graham McKenna (THX response)

    Mr. Stone,
    I just wanted to clarify a few of your comments above. Regarding the Audioholics review of the Lexicon BD player, THX does not certify multi-channel analog outputs of BD Players. In fact, the Audioholics team recently authored an in-depth follow-up piece that examined this very issue and included our position. See the link below:

    Regarding your comment about our specs being vague, this simply isn’t true. The THX specs are in-depth and cover virtually every aspect of a display’s performance. And THX Certified Displays and Projectors continue to be some of the best reviewed products on the market. Our decision not to publish the specs and our compliance process is a business decision.

    If you attend CEDIA, CES or any other industry conferences where THX exhibits, I would be happy to arrange a meeting to discuss any of our certification programs with you personally to help clarify any of the other points you mentioned above. Let me know if you are interested.

    Graham McKenna
    THX Ltd.

  • Bob Stone

    The THX certification of the Lexicon Blu-ray player should cast considerable doubt about the verasity of any THX certification in anyone’s mind.

    When tested, the Lexicon did NOT meet even the most basic THX standards for bass management. See the review.

    THX only provides provides the vaguest of actual specifications while always implying a much more diligent process. Actual tests of THX certified products rarely seem to live up to the hipe of what a THX certification implies.

    THX is paid by the manufacturer and it shows! Note that even the THX spokesperson says they “often” purchase samples to verify compliance. How often, Mr.McKenna, does that occur?

    I’m skeptical it occurs “often”. Please, Mr. McKenna, provide the data of how many THX products you have purchased in the open market to verify compliance. You have NO stated policy of testing EVEN ONCE, a THX certified product, you purchased on the open market. “Often” is very vague!

  • WSmith

    I’m an indie pro video producer/editor so I pay a lot of attention to quality.

    My assumption is that when an HD monitor adheres to the following it’s ready for my primetime enjoyment:

    1)rec. 709 color
    2)10bit per primary color channel
    3)not just LED backlighted but RGB LED backlighted
    4)THX certified

    THX certification seems like a worthy attainment but I list it after the 10bit and RGB backlighting. We are seeing some 10bit panels hit the streets so I’ll continue waiting before I give a monitor my own special five-star certification.

  • Bob Stone

    THX certification provides me with NO assurance.

    CNET just tested the LG 50PK750 Plasma. This is a 2010 model and THX certified.

    Test results for this THX certified display:

    Mediocre Black Levels
    “Relatively Poor performance” in a well lite room
    Failed to handle 1080p/24 properly
    High incidence of temporary image retention
    Color Accuracy was “not equal to the best”
    Motion Resolution “doesn’t match the best plasmas”
    “Strange Video Processing” … “ringing artifacts”
    THX mode “relatively inaccurate gamma”

    I’m afraid the HD Guru has drunk the Kool-aid

  • Joe Pz

    You forgot to mention the panasonic g20 in list of thx certified sets. Nice article!

  • Jason

    I have a LG 47LH90 and the THX mode on it that was suppose to be optimal for movie viewing but it doesn’t really seem that accurate to me. Had the set calibrated and it procuded a much better picture.

  • Kurt Lewis

    WOW, a lot of THX haters here. Let’s give some credit to a company that is at least trying to ensure that what an end user gets is not total Chinese Junk! THX has done a lot to move the bar in our industry for 30+ years and they deserve to be able to get paid for their time just as we do. I attended the second ever THX certification training at Skywalker Ranch and was met by a group of highly skilled and passionate people including Tony Grimanni. I say good for THX!

  • Travis

    THX stands for Tomlinson Holman eXperiment…He was the engineer that developed the system for George. I worked with the Guy, believe me he rubs your nose in it!

  • David

    What amazes me, is that no one seems to know that (if memory serves), THX was sold to creative labs a number of years ago and is no longer affiliated with George Lucas or Lucasfilm.

    Now, while I think that this is horrible news, we must remember that Uncle George also sold off a little company called “Pixar” and look what happened to it after his involvement ended!

    Note that under Lucasfilm, the logo ALWAYS said Lucasfilm ltd THX.

    Just my 2 cents to correct the assumption that uncle George was still running the asylum.

  • unwired

    Its important to note that not all major manufacturers will apply for THX certification, and this doesn’t mean that they produce or sell inferior products. Also, as some of the comments have pointed out, it is patently false that THX label “assures buyers a high quality high definition display”, it just assures that the components in the display are not inferior. This comment in the article is also inaccurate – “If you want an accurate HDTV image, choosing a THX Certified display will get you a top quality unit without fuss.” If you really want an accurate HDTV image, go for professional calibration once the display is installed. For those less discerning, THX is probably your best bet.

  • Derrik Pates

    My XBR8 was unfortunately not submitted for THX approval, I guess. I think it’s safe to say it’d handily whip any of the LG LED-lit LCDs that were, though. With a little tweaking, it’s easily got about the best picture available.

  • Trackster

    The Samsung B8500 is not THX Certified but still gives a majority of the certified sets a run for there money. Who wants to pay extra for a badge?

  • Rob H.


    If only THX actually enforced these requirements before granting THX certification!

    The LG LED-LCD THX displays have inaccurate colour points in THX mode. LG’s THX plasmas have lingering image retention problems. Panasonic’s THX plasmas wash out badly in a lit environment and fail to retain their black levels and contrast.

    But hey…so long as THX gets paid for their certification badge, I guess it’s all ok, right?

    Just like how Lexicon can literally put an Oppo Blu-ray player (case and all) inside of a Lexicon shell and manage to get a THX certification whilst failing basic THX bass management requirements. And just like how Onkyo receivers can have THX certification whilst simultaneously implementing Audyssey room correction in such a way that having Audyssey and a THX listening mode turned on at the same time results in a massively warped frequency output.

    Oh yes, THX certification sure is a confidence booster for any consumer, isn’t it?

    Why not just partner up with Monster Cable while you’re at it?

    Oh…that’s right…you already do!

  • FM

    I think this is exciting. Although, since Panasonic has let their potential buyers down with the +1000 hour black level change, THX should grant their certification after performing tests on sets with over +1000 hour use.

  • Graham McKenna (THX response)

    Hi Tom,
    Thanks for the questions. Although it is not published in the HDGURU article, the THX specification does include a maximum allowable dE, throughout the luminance range.

    The goal of the THX certification is to come as close as possible to reproducing the highest standards for image quality, color accuracy and signal processing performance for TVs right out-of-the-box. However, we do have to factor in manufacturing line tolerances with any product certification.

    To ensure compliance, THX will often purchase displays from retailers and visit production facilities to evaluate products on the line. If we learn that a production unit does not meet our requirements, taking into account manufacturing tolerances, THX works with the manufacturer to improve product performance.

    Graham McKenna
    THX Ltd.

  • Tom

    These seem like reasonable standards, as far as they go.

    However, the failure of the gamut tolerances to take into consideration the brightness of the colors in addition to their chromaticities means that a color could have an extremely large dE color error and still fall within the THX specification.

    The bigger problem is that the 2009 Panasonic plasma THX mode initially had severe color decoding errors that placed at least one of the secondary colors considerably outside of that xy0.005 tolerance. How did this pass THX certification?

  • CB

    Has THX weighed in on the Panasonic black-level problems since that company hypes the “THX Mode” so much?

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