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Re: 4K Blu-ray
CV #407179 09/13/14 01:34 AM
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Having been at CEDIA yesterday, pretty much every demo space had a "4K" projector (most aren't native or "true" 4K) with Dolby Atmos.

Here is the big stuff in relationship to 4K.

You need a very large screen and/or sit fairly close to the screen to really benefit from 4K. That means either a super-sized flat panel (I saw a 16:9 that was a massive 98" diagonal, and a 21:9 extra wide that was 105") or a front projection system with a good sized screen around 115" or larger.

With that said, most of the 4K projectors have other enhancements and hardware to make for a brighter image with better contrast ratio than their lower cost 1080p brothers. So you will still get a nice picture, even if you don't notice the increased resolution.

I did see 1 projector that was actually 4K vs. all of the "shift" technology using 1080p panels and such, and honestly, the "shift" technology looked better than the real deal. I started asking why, and it is because there have been a few years of products in the "shift" or "fake" 4K vs the limited products and experience with actual 4K. It was also talked about in a presentation that it is easier to fool the brain into liking a faked higher resolution than a real one. Not sure of the science behind that, but in the demos I saw it was true.

Now, like Michael says, people would probably do much better to get their displays calibrated than it would be for them to jump to 4K. I noticed a high improvement in my JVC RS-45 projector when I calibrated in a couple of years ago, and while it is probably due for a refresh (since the bulb dims over time) but the picture is so darn good thanks to the calibration. It was honestly like getting a brand new projector again after I calibrated the already amazing picture.

Most people are afraid of the sound of calibration, but you really can do it for about $100. No, it won't be as good as spending $300 or $500 on a meter and a chunk of change for software, but $100 would get you a basic meter and you can use free software, and then follow step by step guides to do the calibration. Of course most meters work with TVs OR projectors, but not both. I think that I spent a couple of hours doing my calibration because I went through the steps once to get the idea of what needed to be done, found out that I made a few mistakes, but got those corrected the second time. I was all gung-ho to calibrate more stuff because it was such a success.

I can't imagine what some of the auto-calibration boxes or a professional can do if I made a huge improvement on my 2nd try.


Farewell - June 4, 2020
Re: 4K Blu-ray
chesseroo #407180 09/13/14 01:39 AM
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[quote=chesseroo][quote=michael_d] Lumagen has a device they call the Radiance Mini. I'd suggest an

Re: 4K Blu-ray
chesseroo #407190 09/13/14 06:23 PM
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Originally Posted By: chesseroo
Originally Posted By: michael_d
Lumagen has a device they call the Radiance Mini. I'd suggest anyone invest in this box a good meter and Chromapure. You can get a bundled package from Chromapure that includes your choice of a Radiance, a meter and the software. I'd give this a try before dumping a ton of money into a new display, new AVR, new cables, etc....

The auto-calibrate function ChromaPure has works amazingly well, even with 3D. I just set the meter up, hit the button and take a nap. 30 minutes later, it's done.

So if i get this right, the hardware box is connected to and sits between a DVDp and the display unit (let's say a LED TV), then runs patterns from the DVDP to the TV for calibration. Images are picked up by the meter, the software analyzes and changes colour, gamma, etc. updating its own hardware box, which then translates to a calibrated signal/visual regardless of what visual settings the TV has?
Or is this solely for projectors only? (though i can see how it might work with a TV as well no?)

The info on their website is rather poorly presented and not particularly clear on their products, requirements, setups...
http://www.chromapure.com/products-autocal-advanced.asp


Chess, for a good and basic tutorial, read through Tom Huffman's (Creator / owner of Chromapure) papers on the web site. They are under the "color science" tab.

The process is pretty straight forward and you can use the Lumagen for any display type. I have a Radiance XS 3D that I use. All source devices go to my AVR first. I have everything set to "native" output resolution, as I do not want the devices messing around with the video data. That's what I use the Lumagen for. So the AVR is the switching device, and it strips audio from the data packet. The AVR output goes to the Lumagen and is output to the projector.

The Lumagen is smart enough to know what the input is, IE: 480P, 1080i, 1080P, 24/60 fps, etc.... You can set it up to remember each input signal, and to have a unique output calibration for each - if you want. I have found this to be unnecessary.

So once you get the devices set up and talking to each other (HDMI BS), you then start the calibration process. The Lumagen I use has internal test patterns, so there is no need to use a calibration DVD. ChromaPure talks to the Lumagen via USB cable. You start the program, and get it to link to the Lumagen. The software then tells the Lumagen to throw up whatever test pattern the software is calling for.

The meters that the pro's use run upwards of 5K. There is no need to spend that kind of money for home use. The Display 3 Pro meter works excellent, and is about $300. It is very accurate and its low light performance is outstanding. I have compared it to my i1 Pro meter and the results are very close (the i1 pro is the most accurate home meter you can buy, but is extreme slow in low light).

So now you have the Lumagen, your laptop and the software talking, you plug the meter into the laptop with USB. The software will ask for your "key" to prove you bought the stuff. It goes through its verification process, recognizes the meter, and you are ready to go.

Low light readings are the hardest for any meter. If you have a projector, it's harder yet. If you point the meter at the screen, the meter can only see reflected light, and it sees this light the distance between the screen and the projector lens + the distance to the meter from the screen. By the time the meter sees the light, it is very weak. One cool feature the software has to over come this, is a meter verification/calibration feature. You can use this to set up a "field" meter and compare the "field" meter readings to a "reference" meter. I use this feature to take a few readings with the meter pointed at the screen with the "reference" meter, then take the same readings with the "field" meter pointed at the lens, and positioned about 4 feet away from lens where the light strength is much higher (to help with the low light readings). The software then compares the two sets of readings and comes up with an "offset". This "offset" is then stored and every single further reading taken by the "field" meter get's this "offset" applied to it. So in a sense, the readings are representative to the reflected image (which can be different than the projected image, depending on screen type).

Once I have the meter set up, pointing at the lens, I then make Gain and Offset changes to the display first. You have to do this, because the Lumagen can not add light, it can only work with what it gets. The software will throw up a 100% white test pattern and a 20% white pattern. You then adjust the displays Brightness and Contrast, and get them set. Then you adjust the display's RGB "offset" and "gain" to get them as close to the target value as you can. After that adjustment, go back to brightness and contrast and verify they didn't go in the weeds. Adjust if necessary. After these changes, you might also make a change to color and sharpness. The whole point in making these display adjustments, is to ensure there is enough headroom and legroom within the grey scale and gamut. For example, if %100 white is actually closer to 70% in the display, it will never get brighter. After you get that complete, you move to the grey scale calibration using the Lumagen output settings. I use the auto-cal function in ChromaPure first, and tweak it manually afterwards. The software will do its thing and it'll make all kinds of changes to the Lumagen output settings and take addition readings to verify the changes. After it says it's done, you save the Lumagen settings. At this point, I will run through the grey scale patterns and take readings to verify the auto cal. I will tweak them a bit to get them closer to a delta E of less than 1.

After grey scale is done, you move to color gamut. If you use the 125 point color-cube function, it takes about twenty minutes. The color cube function adjusts the gamut not only at max saturation levels for each color, but at five different saturation levels for each primary and secondary color (R,G,B,W,Y,C,M). This is what really sets the Lumagens apart from other others. Having an accurate Green at five different saturation levels is what give the image depth and realism.

After all that, you just save the Lumagen settings and call it a day.

Re: 4K Blu-ray
CV #407191 09/14/14 02:25 AM
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So in brief, yes, regardless of what visual settings in my LED TV have, the Lumagen corrects for that by saving settings during the calibration as the software 'reads' images off the TV as is.

I like this idea alot actually.
I went into my LG LED TV settings and changed around some base colour gamut settings to profiles i found online. I can't say i found the end product to be better more so than just a bit different, but the process was really long and droning especially with the slow LG remote interface.
I never bothered going the DVD input for it because i just ran out of patience.

Will have to put this Lumagen idea on my long term wish list but i have so many wines to buy to stock up the cellar first...


"Those who preach the myths of audio are ignorant of truth."
Re: 4K Blu-ray
chesseroo #407196 09/14/14 05:36 AM
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I really wish this kind of functionality was a basic feature of AVRs.

Re: 4K Blu-ray
CV #407202 09/14/14 08:04 PM
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Originally Posted By: CV
I really wish this kind of functionality was a basic feature of AVRs.

And they could sell it for sure, but it would have to add about $1k or more to the cost of a high end AVR.
I for one would consider purchasing that feature though.
They've already done calibration with mics with AVR so why not video?


"Those who preach the myths of audio are ignorant of truth."
Re: 4K Blu-ray
CV #407204 09/14/14 08:48 PM
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Well some displays are coming out now that even the professional calibrators are saying come from the factory with pre-sets that are on-par with a calibrated system. The new line of Sony 4K projectors are getting a lot of praise. So are the JVCs. I don't know much about TV's though...

Re: 4K Blu-ray
chesseroo #407210 09/15/14 12:52 AM
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Originally Posted By: chesseroo
Originally Posted By: CV
I really wish this kind of functionality was a basic feature of AVRs.

And they could sell it for sure, but it would have to add about $1k or more to the cost of a high end AVR.
I for one would consider purchasing that feature though.
They've already done calibration with mics with AVR so why not video?


Just to follow up what "Michael" said, I have had my Lumagen Radiance "Mini" now for over a year and quite frankly, I don't know what I would do without it. The superior video calibrations that can be done with these units are only part of their capabilities. These are quite sophisticated pieces of software that are regularly updated that also provide superb scaling from any source, precise overscan/underscan(I can get my overscan under 1%)and multiple calibration memories for not only different sources but, if you wanted, day and night viewing. The newer 4k processors can provide colour point calibrations in the "thousands" and have built in Darbee, "Darblets", however, they are pretty pricey. From what I have seen from the best and most expensive displays that have built in color/GS systems, they still can't come close to the capabilities and accuracy of the Lumagen products and even if you don't want the processor but still want to calibrate yourself, you still have to buy the software and meter anyway! Actually, the meter/software combination isn't going to cost you much more than a one-time only calibration from a technician, not a bad deal especially if you want to touch it up every so often or if you have more than one set you would like to calibrate.

For those that are not familiar with these processors, I would simply describe them as if you extracted all of the mechanisms in your display that produce the picture and placed them in a separate external box with tenfold the capabilities and precision compared to your display on its own, yet, still able to operate within your display's limitations.

Last edited by casey01; 09/15/14 01:02 AM.
Re: 4K Blu-ray
CV #407219 09/15/14 03:50 PM
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I still need to get a laptop to use the damn thing or i'll have to drag my desktop system all the way over to the media room.
24" screen and all.


"Those who preach the myths of audio are ignorant of truth."
Re: 4K Blu-ray
CV #407261 09/16/14 05:45 PM
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$300 to $500 for a meter sounds cheap to me. The person who calibrated my TV said he paid over $20,000 for his.

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