Review: Sony Bravia KDL-55HX923

Our score: 5/5
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Published: May 31, 2011 11:00 PM
By Pierre-Jean Alzieu / Pierre Anzil
After last year's HX903, Sony's latest flagship TV is the new HX2923.  It boasts the same monolithic design, as well as Full LED backlighting and support for 3D content using active technology.  There are several new features too, including a Motionflow XR 800 filter (400 Hz + backlight sweeping) and a dual chip X-Reality Pro image processor to improve the quality of 2D content.

Features and design

Unsurprisingly,  Sony has once again plumped for its monolithic design on this top-of-the-range model, with a single pane of glass covering the LCD screen.  It looks gorgeous, but is very shiny, so you'll want to make sure it isn't in front of a window unless you're prepared to draw the curtains to avoid reflections.

The manufacturer has managed to slim the frame down, and it now measures just 3.8 cm compared to last year's 6.8 cm.  That's incredibly thin, especially for a TV with Full LED backlighting: rather than having LEDs around the outside, as with Edge LED systems, the diodes are arranged in a grid behind the screen.  That changes everything, and while we don't much like Edge LED, we absolutely adore these new Full LED TVs we've been testing.

As well as offering support for online services and DLNA networks, either via WiFi or an Ethernet port, the HX923 is the first in Sony's collection to offer new features like timeshifting, to pause live TV, and Track ID, to identify the track currently playing.

There are four HDMI ports, and component video, SCART and VGA inputs around the outside of the TV.  There are two USB ports on the side, meaning you can connect two external storage devices: one is used for recording TV programmes and timeshifting, while the built-in media player can access content stored on the other.

Unfortunately, though, the media player on offer here is no better than the one found throughout Sony's 2011 range, with support for only a very limited range of formats.  It couldn't, for example, play our MKV files.  A separate media centre would be a much safer bet. 

55HX920
The glossy screen picks up reflections

55HX920 Inputs


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Remote Controls



All of Sony's TVs use the same remote control, wherever they come in the collection.  The only real difference to the one that comes with the CX520 is that this one has a metallic finish; the buttons also sink less far into the remote when you press them, which is more comfortable.  Disappointingly, there's still no backlighting for the buttons.

LCD Screen

Impressed by its initial results, we decided to take the HX923 apart to find out a little bit more.  A label at the back reveals that the display is manufactured by Sony itself, which is rather curious as we had no knowledge of the firm producing its own panels or having its own technology.

To get a better idea, we decided to take a closer look at the pixels.  As you can see in the picture below, each red, green and blue sub-pixel is actually divided into twelve smaller cells, one on top of the other.  The technology used here can vary the brightness of each of these cells independently.  Even more impressively, groups of four sub-sub-pixels can be turned off, either across a whole line or independently.

We think that this is a PVA LCD display using Full LED backlighting developed by Sony, which would explain why Samsung's name doesn't appear on the label.

Each sub-pixel is divided into twelve cells or 'sub-sub-pixels'.  They can be controlled in groups of four.

Image Quality: 2D

Using the default settings, the picture is decent enough, despite a slightly strong blue tinge.  But once you switch to Custom mode and set the dynamic backlighting to 'standard', the results are quite simply perfect.

Colour reproduction in Custom mode: average deltaE: 1.8

Configured this way, the HX923 is the only LCD TV to get close to what a plasma can do.  That's thanks to a combination of perfectly even gamma and only minimal discrepancies in colour reproduction with a deltaE of just 1.8.



In Custom mode with 'active' dynamic backlighting, we measured a contrast ratio of 3700:1

The dynamic backlighting allows the HX923 to reach an impressive contrast ratio of 3700:1, with deep dark blacks of 0.05 cd/m².  Some TVs can do even better, but the difference is very hard to spot with the naked eye, even with the lights turned off.

The most impressive result of all, though, came when we measured the viewing angles, and the HX923 is the first TV ever to score 4.2/5 in this particular test.  There is virtually no distortion when you look at it from either side, although there are some problems from above and below.  Given that you're not very likely to stand up to watch a film, it's hardly a big problem.

If you are watching a film, we suggest you set the Motionflow filter to 'sharp' and Cinema mode to 'auto 2', which leaves no visible jerkiness or ghosting without any negative impact on the picture quality.

Given that there's no upscaling to be done, HD content is displayed perfectly.  SD content, like ordinary TV programmes and DVDs, isn't quite as impressive.  The HX923's upscaling seems a little lacking in detail and pixellates the image somewhat, and a latest generation console, like the PlayStation 3, will do a much better job.

Clouding and blooming

As well as producing impressively high contrast, that dynamic backlighting also means there's no visible clouding, where light leaks onto dark areas of the screen.  There's no evidence of blooming—glowing halos around light objects on a dark background—either.  All told, an excellent result.

Ghosting and Input Lag

Responsiveness
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This graph shows the ghosting time, measured in ms, that the TV takes to entirely remove the previous frame. The shorter the time, the more fluid moving images will appear

The responsive panels Sony has chosen for its 3D TVs this year keep on impressing us.  The one in the HX923 is one of the fastest we've ever seen, with an average ghosting time of just 8.5 ms.  What hasn't improved is the input lag, which is still 66 ms, or four frames.  That's too high for the fastest gamers, but won't be a problem for anybody else.

Image Quality: 3D

The HX923 is much better in two dimensions than it is in three.  To start with, the on the fly conversion from 2D to 3D is, as is so often the case, more of a gimmick than anything else.  Only a few elements seem to be foregrounded and it's hard to really get the impression you're watching in 3D.  It's entertaining enough for a few minutes, but we soon got sick of it.

With native 3D content, the results are much better, and objects really seem to fly out from scenes with real depth of field.  But despite having such a fast panel, the HX923 suffers badly from crosstalk, interference between the signals designed for the left and right eye leading to objects appearing twice on screen.  Even more annoyingly, any slight movement in the position of your head adjusts the effect slightly, making it even more noticeable.  The further back you tilt your head, the more crosstalk is visible, and beyond an angle of around 45°, the 3D effect is no longer visible.  For the best results, you need to stay facing the screen directly.

Here's what we saw when looking through the glasses (Sony HX923 above, LG LW5500 below):

55HX920
55HX920

With a perfect result, we shouldn't see any trace of the 'R' frame on the left, and, vice versa, none of the 'L' frame on the right. For the time being, only plasmas from Samsung and Panasonic get this right.

The HX923 is supplied with two pairs of 3D glasses. Additional pairs have to be purchased separately and they don't come all that cheap. That's one area where passive technology has a clear advantage!

Audio Quality

In general, the thinner the TV, the worse the audio quality, but the HX923 is the exception to that rule.  Its speakers point directly at the viewers, making it an easier listen, with mid-range and treble in particular well-handled.  There's even some solid bass, too, but it can't hope to replace some dedicated Home Cinema speakers.

Energy Consumption

With the brightness set to produce whites of 200 cd/m², Sony's flagship TV only needs 98 W.  That's not much to start with, but it can vary slightly according to what's on screen because of the dynamic contrast.  Things are just as impressive in standby mode, where we measured just 0.1 W.
5/5 Sony Bravia KDL-55HX923 DigitalVersus 2011-06-01 00:00:00

Pros

  • Excellent picture quality in 2D and reasonable results in 3D
  • High contrast ratio: 3700:1 in Custom mode with dynamic backlighting
  • Very wide viewing angles: 4.2/5, almost as good as a plasma TV
  • No problems with clouding or blooming
  • Good quality audio and low energy consumption: 98 W

Cons

  • Glossy screen picks up reflections
  • Too much crosstalk in 3D
  • Media player doesn't support enough video formats

Conclusion

The HX923 is quite simply perfect when showing 2D content, reproducing colours accurately with excellent contrast. In fact, it's almost as impressive as a plasma TV, with wide viewing angles and a nice even display thanks to its Full LED backlighting. It's a shame we can't say the same about 3D, where there's too much crosstalk. We're more than happy to stick with the incredible performance in 2D.

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