Toshiba 40L3400U LED TV Review
Cheap in the worst ways
Behind The Screens
The Toshiba 40L3400U (MSRP $499, online $399) is not a terrific performer. As you'll see, it's capable of decent performance after an informed calibration, but no amount of tinkering can correct the uniformity issues I noticed during testing and casual viewing. The TV's limited white balance control means you can correct most of the grayscale error (but not all of it). While the L3400U does have some natural strengths, namely its contrast ratio and black level, the bad outweighs the good.
Note that the Contrast Ratio and Viewing Angle results are gathered in Movie mode (or its equivalent) prior to calibration to better gauge the experience that most consumers will have.
Calibrating the L3400U was no easy task. Unlike most TVs, which offer controls for 2- or 10-point white balance, the L3400U only has plus and minus options for its red, green, and blue sub-pixels.
Essentially, 2-point controls let a calibrator adjust the balance between sub-pixels from steps 10-50 IRE (the first half of the grayscale) separately from steps 60-100 (the second half of the grayscale). Even more detailed are 10-point controls, which allow calibrators to adjust RGB along each step of the grayscale. The L3400U's control only allows the user to emphasize or reduce the prevalence of each sub-pixel within the whole, rather than focusing on one half or one tenth of the grayscale. Basically, there's less gradation available.
During calibration, we aim for a peak brightness of 40 fL (about 120 cd/m2) and a gamma sum of 2.4. These are ideal "black room" numbers, the viewing environment that's generally best if you want to see maximum detail and color performance. To achieve these settings, I changed the L3400U's Static Gamma from 0 to -3, and reduced the Backlight from 70 to 53 in conjunction with the noted changes to the TV's white balance and color system.
In most of the following sections, you'll see charts for the before and after effects of this calibration upon the TV's performance. Note that Contrast Ratio and Viewing Angle are taken in Movie mode (or its equivalent) prior to calibration to better gauge the experience that most consumers will have.
A display's contrast ratio is determined by dividing its default luminance at 100 IRE (peak white) by its default luminance at 0 IRE (black). All of our contrast results are gathered from the default settings in Movie mode using a standard ANSI checkerboard at 1:1 pixel mapping in a black room.
I tested a solid black level at 0.04 cd/m2 and plenty of luminance at 172 cd/m2 in the default Movie mode, giving the L3400U a contrast ratio of 4,300:1—not bad at all. Compared to other 2014 LCDs, this Toshiba fosters a more striking contrast between dark and bright elements.
To determine horizontal viewing angle, we measure the screen's contrast from head-on, and then in 10° horizontal increments from the center. In this way, we determine how far from middle a viewer can watch before the contrast is greatly compromised.
I measured a total viewing angle of 18°, or ±9° from the center to either side. Essentially, you have to sit right in the center of the screen to enjoy the best picture while watching this Toshiba.
Grayscale & RGB Balance
A television grayscale refers to all of the neutral shades it creates—blacks, grays, and whites. While a TV's LED backlight tends to create pure light, this can be distorted across the grayscale spectrum by uneven emphasis between the RGB sub-pixel matrix. Essentially, if the TV favors one color over the others, it will add that color to blacks, grays, and whites as well—resulting in reddish grays or green-looking blacks, for example. Prior to calibration, the L3400U tested with a very high collective error of 12.22, where 3 or less is considered acceptable. I reduced this error to 2.24.
Analysis of the L3400U's RGB sub-pixel emphasis reveals that, like many modern LCD TVs, this Toshiba favors the blue sub-pixel over the red and green. Using the TV's 1-point white balance control, I synced up the sub-pixel emphasis as much as possible using the TV's limited software.
Gamma or gamma sum refers to how quickly (or slowly) a TV increases in luminance from black (0 IRE) to peak white (100 IRE). Common gamma pre-sets include 2.0, 2.2, and 2.4, which are better for bright, dim, or dark rooms, respectively.
We begin by measuring the TV's default gamma in the Movie mode pre-set—the L3400U's is 1.65 out of the box. This means that the TV tends to absolutely gloss over subtle details in dark regions. The good news is that it can be fixed: I calibrated the TV and achieved a gamma sum of 2.37—much closer to an ideal setting than before.
A color gamut is a visual representation of a TV's color production. Current HD TVs are expected to adhere to an international standard for color saturation and hue, ensuring that content looks the same on televisions around the world—and ensuring that movies and TV shows look the way the directors intended, amongst other things.
The L3400U does a decent job with color accuracy, but it's definitely not perfect: I had to make some very large changes to the hue, saturation, and brightness of all the primary and secondary colors to hone in on "perfect" coordinates for red, green, blue, cyan, magenta, and yellow.
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