THX began life as part of LucasFilm. The brainchild of Tomlinson Holman, the initial goals for THX was to ensure that movie audiences in theaters heard the same audio that sound engineers heard in the listening booth after the final audio mix. Eventually, that goal mutated, the idea being to ensure that home theater buffs heard the same quality and levels of audio as those sound engineers.

I’ve known about THX and audio for a number of years, even attending level 1 and level 2 training they give to custom installers. That’s where I learned the importance of room acoustics, and how your listening space often affects your listening experience far more than any set of speakers or electronic gear could.

So when I learned about THX getting into the business of certifying HDTVs, I was interested. But before we dive into what goes into a THX certified panel, let’s talk about what THX does and doesn’t do.

What is THX (and What It’s Not)

Once part of LucasFilm, THX exists now an independent, privately held company. The company’s business is split into multiple segments, including training programs, hardware certification and theater design.

There’s some confusion about what THX standards actually mean. Unlike Dolby or DTS, THX tends to stay out of the business of actually altering the signal, though they have dabbled in psychoacoustic effects, such as THX Loudness Plus, which tweaks frequency response to maintain the perception of listening to the movie soundtrack in the sound booth at reference level.

However, THX doesn’t compete with Dolby or DTS in developing primary encoding standards. The training program for audio, for example, gives home theater installers knowledge and tools to design rooms that maximize the listening experience. You learn about acoustic treatments, speaker placement, audio calibration and room design.

Most people only ever see the THX logo on hardware, and think that’s where it ends. From my perspective, the training programs are much more interesting. The audio sessions I attended went into rigorous detail on room calibration, minimizing standing waves, acoustic treatments and more. While incredibly valuable for me, these sessions also highlighted to me the essential conflict about what THX is and isn’t – more on that shortly.

Isn’t THX About Logos on Audio Gear?

Most people, however, know about THX through logos on certified hardware. When you see an A/V receiver, home theater speakers or even PC speakers, there are certain characteristics they all have in common.

On the technology front, THX acts as a consultant in the audio space. For example, the slot-driven speakers used in the THX certified Razer Mako speakers was actually designed by THX. Interestingly, that slot design by Laurie Fincham, was actually designed for automotive speakers. As more cars actually ship with true multichannel audio setups, the slot design is able to deliver adequate sound volumes from the relatively flat areas on the center of the dashboard.

The core idea, remember, is to attempt to recreate the soundscape as the mixing engineer hears it in the sound stage through reference speakers. However, different sets of hardware may reach this goal in different environments. A set of THX certified PC speakers try to recreate that soundscape in the near field environment of a typical PC user – only a couple of feet from the speakers. If you take those THX certified PC speakers and attach them to even a modest home theater installation in a small room, you won’t get that same audio experience.

When THX certifies a piece of hardware – say, an A/V receiver – it works closely with the company building the receiver. Test criteria differ, depending on certification level. The power you need for a THX Ultra 2 certified receiver, which is supposed to fill a fairly large space at reference level is necessarily higher than that needed for a THX Select 2 receiver which is designed for a more modest living room.

At the end of the day, a company pays THX for testing, certification and the use of the logo. Companies which send their hardware through the process may end up not paying for the logo, but still end up with hardware that may be better than at the beginning of the process.

Since the logo program is a major part of THX’s revenue stream, obvious potential conflicts can occur. A company building an A/V receiver can go through all the steps of certification, but there’s no guarantee that actual retail products meet the certification. To its credit, THX does have a random test program, where they go out to retailers and buy sample gear, bring it back to the lab and test it for compliance.

Confusion Begets Controversy
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  • Patrick Wolf - Saturday, March 6, 2010 - link

    Setting your speakers to "Small" and having an 80Hz crossover is not just a THX recommendation. It's a universally accepted method for achieving proper calibration. The only time you set your speakers to "Large" is if you don't have a subwoofer. The auto-calibration on many AVR's often set this incorrectly.

    If your speakers do perform well at 50Hz, you can experiment with the crossover, but you need to set your speakers to "Small". However, your Studio 20's for example are actually rated ±2dB from 54Hz-22kHz. So your crossover should at least be 60Hz.
    Reply
  • SeanFowler - Saturday, March 6, 2010 - link

    I found that adding a subwoofer breathed new life into my Mission speakers, with the Missions set to small even though they're rated down to 40Hz.

    Just because speakers can handle low frequencies doesn't mean you should let them. My Missions were muddy in the midrange because the bass was swamping them.

    Removing that bass from them allows them to do a far better job with the midrange. Result, no muddiness.
    Reply
  • jkostans - Sunday, March 7, 2010 - link

    THX is a waste of time in consumer products, is doesn't mean anything about quality. The audio and video fields are full of smoke and mirrors. Actual calibrated measurements are the only thing you can trust. 90% of audiophiles are idiots that like to spend money and brag about how good their $10,000 interconnects sound. Subjective results are only as good as the person doing the testing. Reply
  • erple2 - Monday, March 8, 2010 - link

    I'd disagree with that. The highly trained ear can hear the difference in quality between the "$10,000 Interconnects", but the reality is that the vast majority of A/V snobs really aren't trained at all.

    The vast majority of people don't know what really does sound "good". Also, calibration is really only good to the consumer, not to the person doing the testing. In fact, you could easily argue that none of the calibration matters to anyone other than the consumer - if it doesn't look or sound good to the consumer, you're just wasting your time. Oh, and it has to actually look good, not look good because some calibration expert says so...
    Reply
  • jkostans - Monday, March 8, 2010 - link

    Just proved my point I think Reply
  • vol7ron - Saturday, March 6, 2010 - link

    Loyd,

    Nice read. I'd be interested to hear more about your "room acoustics" training and possibly setups to combat those problem with small spaces, or worse, small spaces with high ceilings.

    Thanks for the info, I like the breadth of Anandtech's content lately. Not just procs and video cards, but more.

    vol7ron
    Reply
  • gmallen - Saturday, March 6, 2010 - link

    Nice explanation of THX and the lab processes behind the logo. The usual top quality from one of the best writers in the field.
    I consider myself a pretty average A/V buyer; I am not confused at all by the various THX standards, nor by the feature set of a particular product. THX is one thing and feature set is another. Read the literature for the models under consideration, and decide away.
    As for the LCD certification, my local high-end A/V store has a fairly good viewing set-up. The side-by-side comparison of the same model with THX turned on and off shows clearly the superior picture quality of the certification mode. Even sports looks better, to these eyes.
    I conclude that, for me, THX certification in both audio and video is a valuable factor in selecting new products.
    Reply
  • DirtFace - Saturday, March 6, 2010 - link

    When I think of THX I think of George Lucas. And when I think of George Lucas nowadays, the last thing on my mind is quality. Reply
  • erple2 - Monday, March 8, 2010 - link

    Don't confuse Quality Hardware with Quality Content. The former, I think that George Lucas has done some rather impressive (positive) things with. The latter, well, I point you to the Teen Angst riddled shlock of Annakin Skywalker as portrayed by Hayden Christensen (caveat - I was over 30 when those movies came out).

    While the movies were terrible to experience in a language I can speak and understand, the visual and audio splendor I thought was extremely high quality. All of the mechanics of the films were excellent. The other half of my brain, however, died a little watching them.
    Reply
  • erple2 - Monday, March 8, 2010 - link

    Don't confuse Quality Hardware with Quality Content. The former, I think that George Lucas has done some rather impressive (positive) things with. The latter, well, I point you to the Teen Angst riddled shlock of Annakin Skywalker as portrayed by Hayden Christensen (caveat - I was over 30 when those movies came out).

    While the movies were terrible to experience in a language I can speak and understand, the visual and audio splendor I thought was extremely high quality. All of the mechanics of the films were excellent. The other half of my brain, however, died a little watching them.
    Reply

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