With the LH90 Series, LG makes its first foray into LED backlighting, as opposed to the fluorescent (CCFL) backlight used in a traditional LCD TV. The 55LH90 uses a full array of LED backlights behind the screen (compared with the new crop of LED TVs that only place LEDs around the edges of the panel), and it employs local-dimming technology, which means the LEDs respond dynamically to the content on the screen and can shut themselves off to create a deeper black level when necessary.

LED technology isn't the only feature in the 55LH90's repertoire. This 55-inch, 1080p panel also offers THX certification and TruMotion 240Hz technology, as well as LG's Intelligent Sensor picture mode, USB playback of digital files, a ton of picture adjustments, a new automatic calibration tool and the Invisible Speaker System. The two things that are missing, which you can find in other LG televisions, are wireless HD video transmission and LG's NetCast Entertainment platform, which gives you access to Web-based services. The 55LH90's MSRP is $3,000.

The Hookup
The 55LH90 boasts an attractive design: The high-gloss-black cabinet includes a clear acrylic tapered edge that subtly but effectively enhances the overall look. The Invisible Speaker System incorporates speaker actuators into the screen itself, so there are no obvious speakers along the bottom or sides. The TV comes with a rounded swiveling base that has a matching black finish and silver accent. Frankly, the swiveling mechanism made me a bit nervous, as the large 55-inch screen just didn't seem entirely stable; you'll probably want to mount this panel in a more secure fashion, especially if you've got little ones in the house. The supplied remote control has a clean layout, with full backlighting; it lacks dedicated input buttons, but the TV automatically senses which inputs are active and places those inputs at the front of the list when you hit the remote's Input button. The remote also features a button called Q.Menu (for Quick Menu) that pulls up a miniature onscreen dial through which you can make common adjustments, like aspect ratio, picture and sound mode, sleep timer and USB playback.

This TV comes with a comprehensive set of video inputs, including four HDMI, two component video, one RGB and one RF input to access the internal ATSC and Clear-QAM tuners. The HDMI inputs accept both 1080p/24 and 1080p/60 signals, and one is located on the side panel for easy access. Also on the side panel is a USB port that allows for quick firmware updates and supports playback of movie, photo and music files. There's no Ethernet port for Web connectivity, and the TV lacks a program guide and picture-in-picture functionality. Unlike some higher-end panels, the 55LH90 has an RS-232 port to integrate the TV into an advanced control system.

The 55LH90 has an extensive array of picture adjustments, beginning with three preset AV modes (THX Cinema, Sport and Game) that automatically set both the picture and sound parameters to suit the type of source content you're watching. The remote's AV Mode button allows you to scroll easily through the choices; I left the AV Mode set to off so that I could make manual adjustments. In the Picture set-up menu, there are a whopping nine picture modes, including an Intelligent Sensor mode that automatically adjusts the image quality based on the room's ambient light, as determined by a front-panel sensor. Since this is a THX-certified display, it also features a THX picture mode that theoretically should offer the optimal settings to make this panel look its best. I would soon discover that's not really the case, but more on that in a moment. Unfortunately, unlike Panasonic's THX-certified plasmas, LG doesn't allow you to make changes to the picture adjustments when the TV is in THX mode, nor can you even access the advanced menu to see how certain parameters have been configured. Should you choose this mode, you lose access to a lot of desirable picture adjustments that are available in the Expert 1 and Expert 2 picture modes, including the TruMotion 240Hz and Real Cinema set-up options, noise reduction, color gamut, gamma, full white-balance adjustment and individual color management of all six color points. If you plan to have this display calibrated, or at least use an advanced set-up disc like Digital Video Essentials (DVD International), the Expert modes are definitely the way to go.

For those who don't plan to get the TV calibrated, LG has added a fantastic feature called Picture Wizard, an automatic set-up tool that walks you through a basic picture calibration by showing a series of photos and letting you adjust brightness, contrast, color, tint, sharpness and backlight until they match the "recommended" picture. The results don't produce the exact settings I got when using Digital Video Essentials; I made minor corrections to the color and sharpness controls, but otherwise was satisfied with the settings. It's a great tool to encourage people to make their picture look better without requiring advanced set-up knowledge. I especially like the fact that Picture Wizard shows people what edge enhancement looks like (an artificial sharpening of edges) and encourages them to get rid of it. Ironically, this TV has an Edge Enhancer function that's turned on by default and locked in high mode for most of the picture modes, with the exception of the Expert modes. (If you use Picture Wizard, it saves your settings in the Expert 1 mode.) The 55LH90 also offers horizontal and vertical sharpness adjustment in some of the picture modes. If you set these too high, edge enhancement is clearly noticeable; however, if you set them too low, the picture grows noticeably soft. So you want to strike a good balance.

In regards to LG's TruMotion 240Hz technology, the 55LH90 does not actually have a 240Hz refresh rate; rather, it has a 120Hz refresh rate, with a scanning backlight that creates a 240Hz effect. The goal of TruMotion is twofold: to reduce motion blur and to eliminate judder in film-based sources. Unlike some manufacturers that use separate functions to address each of these issues individually, TruMotion deals with both problems using a single menu option, with off, low and high settings. TruMotion uses motion interpolation, which means it interpolates information from the existing frames to create new frames and produce 120Hz. Motion interpolation produces a smoothing effect that makes film sources look more like video, and the low and high TruMotion settings offer varying degrees of smoothness. LG also includes a Real Cinema mode that, according to the manual, shows 24p Blu-ray content at 48Hz if TruMotion is off and 120Hz (5:5 pulldown) if TruMotion is on, both of which should reduce judder, compared with the typical 3:2 pulldown process in a 60Hz display. (If you select the THX picture mode, you cannot access the TruMotion or Real Cinema set-up menus. Real Cinema is turned on, and TruMotion is turned off, which should give you a clue as to what THX thinks of motion interpolation.)

The 55LH90 has an Energy Saving function that cuts the panel's backlight brightness to limit power consumption. The Energy Saving mode includes off, minimum, medium and maximum settings, as well as an auto mode that adjusts the backlight according to the room's ambient light (using the same sensor employed for the Intelligent Sensor mode) and a Screen Off mode that allows you to shut down the video when you're only listening to audio.

Speaking of audio, the Audio set-up menu includes LG's Clear Voice II function, which does a nice job of bringing up the level of vocals to make them more easily discernable. You also get five sound modes, plus bass, treble and balance controls and SRS TruSurround XT processing.

Performance
To evaluate the 55LH90's performance, I compared it with my reference display, the Samsung LN-T4681F, a first-generation LED-based TV that earned high praise from many, myself included. In many respects, the new LG performs similarly to the Samsung and actually shows improvement in several categories. (Samsung has since released a second-generation full-LED model, the A950 Series, but I did not have one on hand for comparison.)

The benefit of a local-dimming, full-array LED backlighting system is that it can turn off the LEDs around portions of the screen to create true blacks, while still allowing bright areas to remain bright. If there's a night sky at the top of the screen, for instance, those LED backlights can be turned off, while the LED backlights at the bottom of the screen can remain on ... and remain bright. The resulting image has excellent contrast, with a greater sense of depth and richer colors. In comparing the two TVs, black portions of the image were comparable, but the 55LH90 appeared to have even better overall contrast, creating a wonderfully rich, dimensional image.

I set the backlight at about 20 to 30 percent, which proved a good fit for dark or bright conditions in my viewing environment; however, the panel can be very bright if you turn up the backlight. I don't recommend a zero backlight setting, as it makes the panel too dim and flattens out the image. The 55LH90 uses a matte screen, so light reflectivity isn't an issue, but I will say that the Samsung Ultra Clear Panel (which is reflective but designed to reject ambient light) rendered a slightly deeper-looking black during the day.

With HDTV and 1080p Blu-ray content, the 55LH90 also did a slightly better job rendering fine details. On a larger 55-inch screen, the picture doesn't have that razor-sharp look you often see on a smaller LCD, but it's not lacking in the detail department.

One of the drawbacks to LED technology in early-generation models is that, because the number of LEDs used in the backlight is not a 1:1 ratio with the number of pixels, the lighting effect is imprecise. For instance, if you look at white text on a black background, the text appears to glow, something that doesn't happen with a plasma TV, in which each pixel generates its own light. In a demo scene from Lost: The Complete Second Season on DVD (Buena Vista Home Entertainment), in which two people sit in front of a campfire at night, the LG produced some unintended glow around lighted areas, and the transitions from light to dark occasionally tripped up the local-dimming function, as it struggled to figure out which LEDs should be on and which ones should be off. Compared with the first-generation Samsung LED, though, this LG model was more precise, with less glow around edges, so the technology is clearly making progress.

In terms of color, the LG and Samsung displays are similar. Both TVs have an out-of-the-box color temperature that veers too cool, even in the Warm color-temperature mode. With the LG, this is true even in the THX picture mode; and, since you can't make any picture adjustments in this mode, you can't dial in a more neutral color temperature. Whites and blacks veer blue, and skin tones look a bit flat, with a hint of red. On the positive side, the LG's color points are very close to those of the Samsung, which is accurate in this respect. The 55LH90's red and cyan needed some tweaking, which again you can't do in the THX mode. In the Expert modes, however, I had all the controls I needed to fine-tune the individual color points and dial in a more neutral color temperature, which made colors and skin tones all the more inviting.

In its handling of 480i DVD and SDTV content, the 55LH90 did a much better job than the Samsung, particularly through the HDMI inputs. As long as the Real Cinema mode was turned on, the LG passed all of my deinterlacing tests with 480i content, both with test discs and real-world demos from Gladiator (DreamWorks Home Entertainment) and The Bourne Identity (Universal Studios Home Video). It's a bit more difficult to make standard-def content look highly detailed on a large 55-inch screen, and the LG's performance is only average in this regard. You won't mistake 480i sources for HD, but there was a solid level of detail in both DVD and SDTV content.

I was also impressed with the 55LH90's handling of some of my favorite DVD tests for black detail, noise and bit depth. While black detail was somewhat lacking in the THX mode, the adjusted Expert mode did a good job with fine black details in The Bourne Supremacy (Universal Studios Home Video) and Ladder 49 (Buena Vista Home Entertainment). The TV rendered a clean image, with minimal noise in the smoke-filled backgrounds of Ladder 49. Facial contours and light-to-dark transitions were smooth with both standard- and high-def content.

The common LCD problem of motion blur is easier to detect on a larger 55-inch screen like this one. That's where TruMotion comes in handy. With the detail tests on the FPD Software Group BD, the 55LH90 produced a cleaner picture with TruMotion enabled; one of my favorite tests shows a camera panning slowly and then quickly over a world map. With TruMotion off, you could not read much of the text. With TruMotion on, it was easy to read all of the city names. During an HD football telecast, finer details in the background were better preserved with TruMotion enabled. If you're especially sensitive to motion blur, I highly recommend you use TruMotion with sporting events.

Low Points
The TruMotion technology is successful at reducing motion blur, but its success in eliminating film judder is debatable. I'm personally not a fan of motion interpolation, and LG's implementation is no exception, although I will admit that the low TruMotion setting is more subtle in its smoothing effects than I've seen with other displays. Still, even when using a 24p source, the low mode occasionally hiccupped and introduced some stutter or smearing, which I find more distracting than judder. Even when I enabled the Real Cinema mode, which the manual says engages 5:5 pulldown (in which each frame is simply repeated five times), it looked artificially smooth, as if motion interpolation was still occurring. So I opted to turn off TruMotion with film sources. If you go this route, however, you lose the blur-reduction benefits. It's a tradeoff I'm willing to make, as I'm less bothered by blur than by interpolation. This issue could be solved by splitting up the blur reduction and de-judder features, the way Samsung does with its newer LED-based displays. Even if you like the effects of motion interpolation, TruMotion doesn't perform reliably with TV signals (most de-judder modes don't), often introducing smearing and stutter into the picture. It's best to use the function only with DVD and Blu-ray movies. With that in mind, I'd like to see a TruMotion button on the remote that makes it easy to turn the function on and off on a source-by-source basis.

It's disappointing that the 55LH90's THX mode isn't more accurate. Black detail could be slightly improved, and the color temperature and color points could be dialed in more closely to accurate standards. Plus, because you can't make any image adjustments in the THX mode, you can't use the THX image as a foundation and go from there to improve the picture. This said, the THX mode is still the best-looking and most accurate of all the 55LH90's preset picture modes, so it's the plug-and-play choice for someone who doesn't want to mess with the picture set-up yet still wants a nice-looking image.

As with most LCDs, the 55LH90's viewing angle is only average. Bright scenes retain decent saturation at wider angles, but darker scenes look washed out, and black detail is lost.

Finally, while the 55LH90's video processor does a nice job of de-interlacing 480i content, it surprisingly falls short with 1080i film-based sources. The TV failed the film resolution loss test on the HD HQV Benchmark BD, and it produced blatant moiré in the stairs at the opening of chapter eight of the Mission: Impossible III BD (Paramount Home Entertainment), with my Pioneer BD player set for 1080i output. This isn't a concern when you're mating the TV with a good Blu-ray player that outputs all discs at 1080p through HDMI, but it is a concern with HDTV content, as a number of channels transmit the signal at 1080i, including CBS, NBC, TNT, and others. I noticed more jaggies and other digital artifacts than I usually do on these stations. Frankly, I'm surprised that a THX-certified display would fail this processing test.

Conclusion
This proved to be an interesting review. Two of the 55LH90's big-ticket features - the THX mode and TruMotion 240Hz - didn't exactly wow me. I recommend calibration over the THX mode, and I would only use TruMotion with sports or video game content. Yet the success of the 55LH90's marquee feature - LED backlighting with local dimming - overshadows the other issues. Take some time to set up this TV properly, and you'll be rewarded with a great-looking picture. Furthermore, the 55LH90 is loaded with picture adjustments and connections, and the cabinet design is easy on the eyes to boot. At $3,000, the 55LH90's price is on par with Samsung's LN55A950 (which is no longer available through Samsung) and much less expensive than Sony's KDL-55XBR8. If you're in the market for a big-screen flat panel and desire a higher level of performance than a traditional CCFL LCD can provide, LG's 55LH90 is definitely worth a closer look.