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KDL40W3000 Calibration & Benchmark

by Vincent Teoh
16 October 2007

Pre-Calibration Correlated Colour Temperature (CCT)

On the remote control there is a [Theatre] button – meant to provide the best image settings – that in practice simply summons the [Cinema] mode. Out of the box, the [Cinema] mode (default [Colour Temperature] "Warm 2") on Sony KDL40W3000 yielded a CCT which was overly warm, although among all the picture presets this still came closest to 6500k:

Baseline CCT Baseline RGB Tracking
Baseline "Warm 2" CCT
Baseline "Warm 2" RGB Tracking

Greyscale Calibration

The Sony KDL40W3000 offers white balance adjustments in the user menu, preempting any need to break into the service menu (and hence void the warranty) to calibrate its greyscale. With each picture preset being fully customisable to different inputs, I saw no reason to use the [Custom] mode, and so carried out the calibration in [Cinema] mode.

Calibrated CCT Calibrated RGB Tracking
Calibrated CCT
Calibrated RGB Tracking

It did not take me much time to achieve an excellent result: from 30% stimulus onwards the greyscale came within a whisker of D65 with delta errors (dEs) of less than 2 throughout.

Pre-Calibration Colour Chromaticity

Besides the obligatory [Colour] control that affects both saturation and intensity in uncertain measures (the [Hue] control is disabled over HDMI), the Sony KDL40W3000 boasts no less than 5 options in the on-screen menu that can define the final colour gamut, namely [Colour Space] and [Live Colour] in the [Picture] submenu, and [x.v.Colour], [Photo Colour Space] and [Colour Matrix] under the [Video Settings] submenu.

When watching non-xvYCC movies and broadcast programmes, we only need to concern ourselves with [Colour Space], [Live Colour] and [Colour Matrix]. I will let the following CIE diagrams do the talking:

Wide Colour Space [Live Colour] High
[Colour Space] "Wide"
[Live Colour] "High"

Two [Colour Space] options are available: "Standard" and "Wide". The latter resulted in a green primary that was mildly off-hue. Engaging [Live Colour] (active only in [Colour Space] "Wide") either in the "Low", "Medium" or "High" setting would progressively increase the saturation and hue inaccuracy.

[Colour Space] "Standard" reproduced colours more naturally and accurately. Depending on the type of incoming video signal, you can further specify the colour space standard through the [Colour Matrix] control: "ITU601" for standard definition, and "ITU709" for high definition. Do not worry if you are confused... simply set the [Colour Matrix] to "Auto" and the Sony KDL40W3000 will automatically use the resolution of the content to decide on the correct colour standard.

ITU 601 ITU 709
[Colour Matrix] "ITU601"
[Colour Matrix] "ITU709"

From my testing, if the resolution of the video signal was 720p and above, "ITU709" would be used. The resultant primary and secondary colour points came quite close to matching the Rec. 709 HD colour space standard when plotted on a CIE chart.

For resolution below 576p, the television would kick into "ITU601". Prior to calibration, this presented a slight problem because Rec. 601 is the colour standard for NTSC material, yet we are in PAL land. When measured, the colour points conformed almost perfectly to Rec. 601 standard, but fell short if PAL system is used as reference.

Colour Calibration

Post-calibration colour gamut on the Sony KDL40W3000 was among the best I have seen on any flat panel television, a remarkable achievement especially given the absence of tint control (for non-NTSC material) and any meaningful colour management system. For high- definition, primary and secondary colour points were almost bang on the Rec. 709 standard:

HD Colours 709 reference

In the end, standard-definition colours did not venture too far away from the PAL encoding standard:

SD Colours PAL reference

Benchmark Test Result

Dead/ stuck pixels 0
Screen/ backlight uniformity Reducible clouding; sides slightly lighter than centre
Overscan 0% with [Display Area] set to "Full Pixel" (1080 source) or "+1" (only 720p on HDMI); and "Full 1" & "Full 2" (VGA)
Blacker than black Passed
Black level Excellent
Black level retention Auto dimming when screen is black/ almost black
Colour chromaticities Excellent
Scaling Average
Video mode deinterlacing Average; limited jaggies reduction
Film deinterlacing ([Film Mode] on) Quick 3:2/2:2 detection, but loses the lock now and then
Viewing angle 90°
Motion blur Normal for a high-end LCD TV
Digital noise reduction Very effective, but introduces motion trails
Sharpness Defeatable edge enhancement
1080p/24 capability (PS3) Accepts 1080p/24 signal from PS3 – no telecine judder
1:1 pixel mapping Yes, when [Display Area] is set to "Full Pixel"

Black Level

From objective quantification, the Sony KDL40W3000 was neck-and-neck with Samsung LE40F86BDX in terms of post-calibration black level, although subjectively the latter looked a shade darker due to its reflective Super Clear Panel™.

Unfortunately Sony has chosen to implement undefeatable auto-dimming on KDL40W3000 presumably because their customer service and returns departments have had enough of complaints about backlight clouding. Whenever a black or nearly black image comes on (e.g. fade-outs or end credits), the residual light output on screen would drop abruptly after four seconds. This dimming effect would remain in place until the overall screen luminance surpasses a certain threshold, at which point light output would be almost instantaneously restored, rendering the black level fluctuation all the more noticeable.

The good news is that the right settings (and some ambient light) can go a very long way towards making the auto dimming on Sony KDL40W3000 less distracting. The trick is to minimise the difference between calibrated black level and the absolute lowest black level on the set without sacrificing peak brightness.

Screen/ Backlight Uniformity

Even without the aid of auto dimming, there was significantly less backlight clouding on the Sony KDL40W3000 compared to the W2000 we reviewed 7 months ago. Again, by shooting for the lowest black luminance while maintaining sufficient top-end brightness, this backlight scourge can be attenuated to truly negligible levels.

While evaluating screen uniformity through full-field test patterns, the darkest ones (e.g 10% stimulus) revealed the sides of the screen to be just a tinge lighter than the middle. I doubt anyone but the most discerning owners would even pick it up in normal viewing.

Detail & Resolution

The Sony KDL40W3000 fully resolved every horizontal and vertical single-pixel-wide detail from a 1920x1080 source over HDMI and component, with the former digital connection providing a marginally cleaner response. I did not manage to make 1920x1080 from PC VGA work on the Sony KDL40W3000 (the result was a cropped desktop), but that might just be down to my ATI video card and/ or driver version.

Video Processing

I'm disappointed at the quality of video processing on Sony KDL40W3000. Let me explain.

The Sony KDL40W3000 is supposed to feature the Bravia EX video processing engine, the same one that's used on the X2000 range (flagship of the previous generation). However, for 480i/ 576i SD source I found its scaling and video mode deinterlacing to be no better than the Samsung F86: detail was on the soft side, and more than a few jaggies were observed. Engaging the DRC mode improved matters somewhat, but introduced excessive ringing and edge enhancement.

With [Film Mode] set to either "Auto 1" or "Auto 2", the Sony KDL40W3000 detected 3:2 cadence very quickly over 480i, but locking was not steadfast so the television would drift between video and film mode deinterlacing for film-based content, resulting in intermittent moire and twitter. The same phenomenon was witnessed on PAL movies over 576i (2:2 pulldown). The DRC mode only worsened the poor lock, and so should be disabled when watching film material.

Things were better on 1080i. Jaggies were kept to a minimum, and as long as DRC mode was left off, 1080i was deinterlaced to 1080p without any loss in resolution. [Film Mode] didn't prevent the television from failing the 3:2 cadence test pattern over 1080i from HQV Benchmark Blu-ray Edition, but as far as real-world programme material was concerned, proper film deinterlacing was still applied, as evidenced from the elimination of line twitter from the swaying cages in Chapter 11 of King Kong HD DVD.

For correct mixed edit detection, [Film Mode] needed to be disabled, otherwise combing would creep into horizontal scrolling text overlaid upon film material.

Noise reduction on the Sony KDL40W3000 was competent enough at baseline, but if you ever felt the need to stabilise the picture further, even [Noise Reduction] "Low" did a stellar job. Crank it up though and you'll start seeing motion trails. To be perfectly honest, I prefer leaving [Noise Reduction] "Off", as was the case with [MPEG Noise Reduction] which cut out too much detail with its spatial filter.

It would be criminal if the newer Sony HDTVs did not handle 1080p/24 properly, considering that this unmolested video output directly from Blu-ray discs is one of the major strength of another of Sony's key offering, the Playstation 3. There was never any doubt that the Sony KDL40W3000 would pass this with flying colours, removing telecine judder without any fuss.


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