Toshiba SV685 (46SV685) LED LCD TV Review

AVForums reviews an LED-based LCD with Local Dimming.

by AVForums
TV Review

1

Toshiba SV685 (46SV685) LED LCD TV Review
SRP: £2,099.00

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We’ve seen a boatload of LED LCD TVs lately, but most of them have been of the side-lit type, meaning that they aim for a slim form factor rather than higher picture quality. Such is the apparent mania surrounding those displays (hey, they’re slim, that’s all that matters, right?), one manufacturer has even decided not to bring its higher-quality LED back-lit display to the UK.

Fortunately, Toshiba have their heads screwed on, and have the 46SV685 ready for UK consumption. This is the company’s high-end 46” LCD TV, so you probably won’t be surprised to hear that it has a 1920x1080 panel, Toshiba’s 200hz system, and of course LED backlighting with local dimming. Local dimming means that the LCD panel is illuminated by several independently controllable LED lights situated behind the screen. Since they’re independently controllable, they can be darkened or brightened depending on the areas of the screen, allowing for greater mixed-scene contrast. Let’s see if the 46SV685 has what it takes to fight off LCD’s long-running contrast problems.

Styling

The 46SV685 is a weighty TV, but we can hardly hold that against it – after all, how often will you be moving it around? This weight is probably largely due to the sheet of glass that makes up the flat front panel. Around the screen itself, there’s a fairly thick black border which features Toshiba’s trademark “silver stippled” finish near the edges. The “TOSHIBA” logo also illuminates, but this feature can be turned off when it proves distracting. All of this is branded by Toshiba as the “Deep Lagoon” design.

The display features 4 HDMI inputs (one is on the side), 2 SCART terminals, Component video inputs, a PC input (analogue RGB), a LAN port, a USB port, and legacy S-Video and Composite Video inputs with accompanying audio jacks. There’s also an SD card input.

Menus and Set up

After turning the display on for the first time (via the Power Switch on the far left), you’re asked if you want to tune Analogue channels, Digital channels, or both (I appreciate being able to skip the Analogue tuning rather than having to mash the “CANCEL” button half-way through). Following this, you’re given the option of “Home” or “Shop”, indicating where the display is installed. Selecting “Shop” defaults to the ultra-bright viewing mode suited to fighting storeroom lighting, whereas “Home” is a little more subdued.

The menu screens hold few surprises – pressing the MENU button on the remote immediately displays the most common Picture controls, which all act as expected. Moving into the Advanced menu, we’re given an On/Off switch for the 3D Colour Management System, a second option to actually alter what the 3D CMS is doing, an Auto Brightness Sensor control, and even an option to enable or disable the LED local dimming technology, called “LED Backlight Control”. Turning this off keeps all of the LED lights lit at once, and essentially makes the TV act like a standard CCFL-backlit LCD TV.

Next, we have two options which let us control the Gamma characteristics of the TV (to an extent). One of these is “Black/White Level”, which allows you to alter the gamma curve of the set (I measured “0” as being the least wacky, but more on that later). “Static Gamma” allows for further Gamma control.

As well as some detail-killing Noise Reduction controls (best left disabled), Toshiba’s Resolution+ technology is present in the menus, and offers several degrees of severity. Although this feature does increase perceived detail with SD content, you’ll need to be sitting fairly far back to benefit, as it also enhances compression artefacts and other nasties. Absolutely do not use it with HD material.

Moving on, we have the Active Vision M200 system, which combines motion compensated frame interpolation with LED scanning to increase motion resolution. There are several similar systems which attempt to solve the age-old LCD motion blur issue, but I’ve not found any of them to be a genuinely worthwhile fix. Toshiba’s is little different, as it can produce motion artefacts (of course), but it does have the distinction of not causing film content to look overly smooth.

Lastly, there’s a “Film Stabilization” option, which conceals both the cadence detection (Film Mode Deinterlacing) and motion interpolation controls. If you set it to “Standard”, you’ll get just the Film Mode detection and none of the silly sped-up motion. There’s also an “Expert Mode” menu, which allows the user to turn off the Red, Green and Blue elements of the picture. For example, you can shut off Red and Green to create a Blue-only mode. This is useful for setting the “Colour” control with test patterns.

Features

Asides from the standout LED Local Dimming element, the 46SV685 also features Dolby Volume, which is an intelligent volume normalizer (the idea being that differences in level between TV shows, adverts, and across different inputs, shouldn’t require you to reach for the remote). The TV is also DLNA certified, meaning that it should play nicely across your home network.

Measured Results Out of the Box

Although not entirely consistent, the TV’s performance after a basic calibration (correct setup of the Brightness, Contrast, Colour and Sharpness controls, and “eyeballing” the nearest-to-accurate Colour Temperature) was passable. Most Greyscale errors (DeltaE on the chart) scored at around 2, meaning that the colour of grey should appear correct to the average human eye already. Unfortunately, Gamma tracking was a different story, with the display producing images that were somewhat darker-than-spec until about 70% brightness.

Colour was much the same: the Green primary colour was most noticeably oversaturated, and Red and Cyan were somewhat off-hue. Of course, the display features a 3D CMS, so it was my intention to clean this up as much as possible.

Calibrated Results

The calibrated results from this display were a little disappointing. After hours of work, I was unable to get linear Gamma tracking, which appears to be an annoyance associated with the behaviour of the LED dimming. It appears that the display has (inadvertently or not) been designed to keep the LEDs dimmer than standard at 60% brightness and below, and higher than standard at 70% and up, to maximise the perceived “richness” of the picture. Personally, I find that Gamma oddities are far easier to forgive than colour issues, but your mileage may vary on this issue. If you're sitting here scratching your head, then you probably won't notice or care about this, but die-hard videophiles should know about the behaviour.

In terms of Greyscale tracking, the story was much happier. Although the RGB Level Tracking chart might not look too pretty, remember to always pay attention to the scale, and you’ll see that deviations are only a couple of percent. Most errors here scored 2 or below (OK, one is JUST over 2!), which shouldn’t be noticeable to the human eye – at least not outside of test patterns.

Colour was also a little disappointing. After using the 3D Colour Management System along with a measuring device, it soon became apparent that the controls Toshiba provided weren't going to be of huge use in perfecting the display’s output. Although the CMS offers control over the Hue, Saturation and Brightness of all 6 colours (the 3 primaries and 3 secondaries), in reality, the scope of these controls is limited, for a few reasons. First and foremost, like other Toshiba displays, beyond a gentle click or two, the “Brightness” control is essentially useless for correcting Colour Luminance because it reveals huge levels of noise in the areas it works on. Secondly, it turns out that adjusting the Saturation of the colours also has a huge knock-on effect on their Luminance, and we can't correct this afterwards due to the aforementioned issue. In the end, a small cleanup was all I could really accomplish with this display, but at least this resulted in errors of around 3 or below across the board. This resulted in noticeable, but not unforgivable colour errors (depending on your individual sensitivity, of course).

Video Processing

The 46SV685’s video processing is average. Toshiba’s Meta Brain processor does a decent job of scaling SD content to the 1080p panel, but disappointingly for such a high-end display, the TV failed the 2-2 PAL film mode detection test, meaning that SD movies from the TV’s own tuner or from a standard definition cable or satellite box won’t always look their best. Fortunately, in real world usage, the TV did a better job, but wouldn't always stay in Film Mode. (For those of you with NTSC material, the 3-2 test passed for this TV system, but none of the others on the Silicon Optix test disc did).

The TV does a decent job of disguising jaggedness in Deinterlaced Video material. Small jaggies are visible at all times, but never to an irritating extent. All the same, this performance is somewhat underwhelming, especially given the emphasis Toshiba’s promotional material has put on their TV’s upscaling capabilities in the past.

Picture Quality

For all its other inaccuracies, once fed with a high-quality source such as a Blu-ray Disc, the 46SV685 can put out a fairly nice looking image. 24p content is reproduced faithfully without judder, and provided the noise reduction controls are shut off, the full 1920x1080 pixels from the signal reach the screen without distortion. There is no Colour Bleed (Y/C Delay) or bandwidth limitations in the Luminance or Colour channels, which is excellent.

Since this is a local dimming LED display, it would make sense to discuss how well this works in combatting LCD's traditional contrast limitations. The answer is: somewhat well.

When you’re on-axis (that is, not watching the screen from the sides), the effect is at its best. Dark areas of the screen are somewhat dark, with noticeable but largely unobtrusive light spill from surrounding areas. Remember, there is a limited number of LED lights behind the LCD screen: each pixel does not have its own corresponding LED light source but instead must share it with surrounding pixels, so this so-called halo effect can occur (see image, right). From the sides, the usual LCD issues of decreased contrast and shifting gamma are visible to a minor extent, except when those areas are totally black (because the LEDs for those portions are shut off). It’s also worth noting that the LED lights take a small amount of time to react to changes in brightness on the LCD panel, so the effect is not entirely seamless. With all of those quirks noted, keep in mind that my reference is with Plasma display technology, which is still the current flat panel state-of-the-art. When compared to conventionally backlit LCD TVs, local dimming LED is superior.

For Digital TV sources from its own tuner, the 46SV685 does battle with the hideous quality broadcasts in what’s probably the smartest way – it appears to leave them alone. There’s no forced MPEG noise reduction or other processing at work, which is just as well, because aggressively filtered compressed video can often look worse than the original input.

Gaming Performance

The 46SV685 continues the LED LCD trend of having higher input lag than conventional CCFL-backlit LCDs, which makes sense when you factor in the additional processing required. There are several picture modes in the menu, but gamers should select the “GAME” preset to cut input lag down to a probably acceptable (but not lightning fast) 34 milliseconds. This is an improvement from the “MOVIE” mode I used for calibration, which weighed in at a more noticeable 54ms.

Energy Consumption

0 IRE (Black)

50 IRE (Grey)

100 IRE (White)

Local Dimming On

60w

123w

159w

Local Dimming Off

137w

165w

159w

Conclusion

Toshiba’s 46SV685 is not an astonishingly well performing display, but it is an expensive one. Other than the commendable post-calibration Greyscale performance, there is really little that stands out about this display other than its price tag. At around £2000+, the 46SV685 competes with Plasma displays which offer better motion clarity, better viewing angle characteristics, and no LED quirks, since they are self-illuminating.

Although I’m quite happy to watch and game on a 46SV685, its price tag, coupled with its lack of absolute excellence, make it difficult to offer it as a stand-out recommendation to new TV buyers. If you have a genuine reason for not wanting a Plasma display (other than an irrational fear of the technology!) and must have a local dimming LED LCD TV, then Toshiba’s is one of your only choices, and may prove its worth to you based on this alone.

Scores

Sound Quality

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8

Smart Features

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.
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7

Ease Of Use

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.
.
7

Build Quality

.
.
.
7

Value for Money

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.
.
.
.
.
.
3

Verdict

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.
.
6

Picture Quality

.
.
.
7

Video Processing

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.
.
7

Greyscale Accuracy

.
.
8

Colour Accuracy

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.
.
.
6

Contrast/Dynamic Range/Black Level

.
.
.
7

Screen Uniformity

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.
.
7
6
AVForumsSCORE
OUT OF
10

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