Calibrating Hi End projectors: the four pillars of THX and a pickle with a cut glass

The THX guru was as welcome in New York as a magician Copperfield. And the gurus are here. On this occasion, a joint seminar of JVC dealers and THX engineers took place at Digital Systems. Professional installers discussed how to calibrate and tune Hi End projectors. I, too, was unheard of to see such a rare action with my own eyes.

Projectors

JVC Hi End received THX certification

Basic information for those who aren’t crazy about THX

Not many people in our country are familiar with the TXH acronym. And even fewer video enthusiasts know that it is not just a button on the remote control of the projector or TV. It is a whole system of knowledge, if you like – the philosophy of the ideal Hi End…

The speakers were experts:

• Jon Cielo, Engineer and THX Standards Developer
• Matt Severaid, Senior THX Marketing Manager

A little history. THX was created by George Lucas after he became frustrated with the transmission of his vision for Star Wars. It had to do with poor video room acoustics, faded pictures..

After that, Lucas decided to develop and implement standards in sound and picture quality. Thus, THX’s mission is to accurately convey the director’s vision.

Why the THX logo arose? Apparently, because this standard was first used in THX1138. Areas of THX’s “jurisdiction” include professional studios, movie theaters, mobile applications, projectors and displays, home theaters, BDs, car audio and even video games. THX has many certification programs. But in this review we focus on premium projectors.

Under the “jurisdiction” of THX are such areas as professional studios, movie theaters, mobile applications, projectors and displays, home theaters, BDs, car audio and even video games.

Do you trust what you see on the screen??

The seminar was really interesting because the professionals discussed the quality of images in the home theater in the finest details.

Alexey Sokolsky, JVC product manager, made an opening speech.

It’s no secret that JVC projectors are the absolute leaders in natural contrast. Also worth noting is the eight-tone picture enhancement system based on analysis of the pixel structure of the picture.

We have already published detailed reviews on the top range of JVC projectors: it is presented by three projectors: DLA-X900RBE, DLA-X700RBE, DLA-X500RBE. These are Full HD projectors, with the ability to project a resolution of 4K 3840 x 2160 pixels , achieved through an optical processor using e-shift 3 technology. The most important difference between them is the contrast, which is different in different models – 150000:1, 120000:1 or 60000:1 read the comparative test of the JVC top line .

Of course, with the Hi End background, the topic of calibration also came up: how relevant is it to the projectors at this level?? It’s hard not to agree with Alexey Sokolsky, who made the following comparison: it would be strange to buy a Porsche and drive it on bald tires in front of an amazed public. Buying a true Hi End, it is just as strange to save on calibration and not use a projector for everything: it has almost unlimited options for adjusting image quality.

And then, you might say, the conversation about projector setup moved into the realm of mysticism. The fact is that there are things in the image on the screen that we believe without any questions, but there are also things that we hardly believe or do not believe at all.

The main task of the image on the screen is to transmit the director’s idea. To do so, the subject gets into the frame, moves, acts, unwinds the storyline, sometimes enhancing the script with personal charm. Every now and then the light in the frame changes, colors flicker…

If we see an elephant walking on the screen, we won’t doubt it for a second: an elephant is an elephant in the frame. In this case there is an absolute benchmark for visual “face control”. But having an elephant in the frame might not be enough to convey all the nuances in brightness, light and color – more fine adjustments are needed here..

Let’s take, for example, the color scheme. Of course, color film is more realistic and pleasing than black and white film. But this is not the only point. Any psychologist will tell you that certain colors influence our mood and our perception of what we see on screen. That’s why it’s called color temperature. Closer to blue – it seems to us that it is colder in the frame, yellowish tones appear, it becomes warmer and even cozier, etc.d.

And here you have to wonder if the color reproduced by the projector or TV corresponds to the director’s idea? Far from it… More than that, we’ll never know if it’s true or not, if we don’t take special action.

Let us follow Alexey Sokolsky in his experiment with cucumbers: imagine a fresh green cucumber with some spring water in a glass and the same still life as a salty cucumber with the same faceted glass. Do you have any doubts about the strength of crystal clear filling of cut glass in the second version?

And the difference between the two pictures is just a slight color shift, which completely changes the perception of what is happening on the screen.

And now the main question: What did the director want to show?? Fresh cucumber or salted cucumber? If the dude on the screen pours a glass of glass and then crunches a fresh cucumber, he obviously screwed up something with the color: the director always tastes salty..

Feel how important color can be?

I think there are very few people who doubt that light and lightness are no less important than color. It’s the luminance that determines whether we see something on the screen, and allows us to judge the volume of an object.

Modern television series, especially the police and fantasy genre, abound scenes with low lighting: in various kinds of basements, in the forest at night, in the gloomy ruins… Such scenes have a tiny difference in the lighting of the object-hero or anti-hero and the surrounding ambience. That’s why it’s important that the projector should render the subtlest shades of contrast in areas close to full shadows.

Here’s a shot from the famous Lord of the Rings trilogy. A decent projector will show just about every detail in the shadows.

And this is how the same image looks like if the projector has too little contrast in the dark areas. As you can see, the shadows have become a dark, indecipherable blur.

Here’s another example – concerning the volume of the object: without light a sphere turns into a regular circle. As soon as the light returns, the circle becomes a sphere again.

In the third picture I made a little fun of the brightness curve and this is what I got. The color remains the same, so does the object, but how has our perception of the sphere changed?!

Like the cucumber, whether it’s fresh or salted, we have no reference with shadows either, so we can only trust what we see on the screen.

The moral of the fable: calibration is the only thing that can give you a semblance of reference and confidence that you’re seeing exactly what the director wants you to see. And believe me, you get much more pleasure from watching video on a calibrated device.

By the way, you can distinguish two different principles of calibration – it is hardware and software.

Software calibration

involves the often fully automatic creation of a color profile for a particular projector in conjunction with the screen.

Pros: Calibration is usually automatic. You don’t need a lot of knowledge to perform it.

Cons: In this case, you must have a video source operating system – for example, a computer, and capable of working with a color profile. So you can’t calibrate your home theater receiving the video signal from a BD player using the software method.

Hardware calibration

Involves changing the settings in the device itself. This option also has a number of pluses and minuses.

Pros:

– You can calibrate practically any output device a projector, an LCD panel, etc. , and it is not necessary to change any parameter.d. regardless of the source.

– Much less likely to cause artifacts inherent to software calibration, e.g. on color bars in a black and white gradient.

Cons:

– The quality of calibration will depend on the capabilities of the device’s engineers. For example, the adjustment of gamma curves at different brightness levels I’ve only seen in JVC projectors.

– The calibration process is extremely complex and requires special skills. In brief – changing one parameter inevitably leads to changing others. In such a dynamic system, finding the right golden mean is insanely difficult, if not impossible.

However, there is something else besides calibration that can provide the highest level of image quality…

THX: A perfect picture at the touch of a button?

How do the THX engineers test projectors before they give their approval for the lettering on the case??.

Verification is performed in three ways:

– Color rendering – evaluates the accuracy of primary and secondary color reproduction, contrast, etc.d. Read more about this in our review “How to choose a projector: rating – anti-rating parameters”.

– Backlighting across the screen – the backlighting should be uniform along the edges and center of the image.

– Dynamic tests – to check for artifacts in various dynamic scenes.

Separately we would like to dwell on the moments that can not be calibrated at home.

It is primarily the uniformity of backlighting. How important it is, judge for yourself

The display on the left has a very uneven backlight, the image on the edges will be very different from the center, creating a vignette. Certified displays don’t have this image disadvantage.

As an example of one of the dynamic tests, the de-interlacing test. Its essence is as follows: in a circle of alternating bands of green and red pixels, inside this circle a gray circle flies. On a non-certified display, the pixel bars merge into a mustard monolith, but not on a certified display.

Thus, the certified projector has a number of features that qualitatively distinguish it from others. It’s important that many of the parameters checked by THX can’t be calibrated by the user.

However, to be fair, it is worth noting that if your projector is not THX certified, it does not mean that the device is bad at all. Far from it. For example, the junior model in JVC top range does not have one, but it does not cease to be an excellent projector.

Certification of home theater systems rests on four pillars: room, system, equipment, installation

It is important that in case of not meeting one of the requirements, we can not talk about THX home theater.

So the first column in the picture above is the installation room requirements. For example, there should be no extraneous noise in the movie theater. If you can hear the kitchen with a boisterous neighbor or an equally boisterous TV with the same mother-in-law through the wall, then, alas, such a room is suitable for some other entertainment.

The shape of the room and more also matters. The figure shows an example of calculations of the various parameters of the room, made by experts THX.

The system assumes that the viewing angle of the screen should be 40-50 degrees. And also the requirements for the positioning of the speakers – the front speakers must form an angle of 45 degrees to the listener, the rear speakers at 90 degrees to the listener.

Choice of equipment. In order for the second pole from the same picture above to stand upright, the user is supposed to choose ALL THX-certified equipment – audio receiver, amplifier, speakers, display, projector, etc.d. Otherwise, your home theater will not be certified under THX.

Installation. This step involves directly installing and configuring the equipment, checking its operation, as well as calibration. You did not misunderstand, calibration even with THX equipment is also necessary. But in this case it’s what’s called fine-tuning, which is the tiniest of edits. If you want – polishing the knife, after sharpening it.

So, if you think about a serious home theater, have a budget and are willing to change the layout of the house for the sake of it, you can contact the experts at THX and they will do everything “turnkey”. Is it worth it? The question is how much of an aesthete and connoisseur you are. Following the recommendations for creating home theaters, you can make your home theater is not much inferior to certified.

As for the general public, this certification is clearly not for everyone. If only because none of the modern standard apartments do not meet the THX requirements..