CurtPalme.com Home Theater Forum

**kal** · Posted: Sat May 06, 2017 2:30 pm Post subject:

Chris - sounds like you're the expert and know exactly what you're doing, so we'll stop offering suggestions. I'm sure calibrating a projector used for Home Theater to 3 ft-L would look phenomenal. Rolling Eyes

Kal

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

No, I don't think it would. The 3 ft-l calibration was required to (a) reduce maintenance costs (the sims usually run at least 12 hours a day with mostly static imagery so screen burn is an eventuality) and (b) for reasons relating to compatibility with night vision equipment. I was not permitted to see the sim in operation in night vision mode so I can't tell you if they would have even
developed a visible image in that mode but of course it does require a level of black performance that you probably don't need in a home theater calibration.

I would appreciate it if you were to simply accept two facts: Having the disc is a matter of simplicity and convenience for my specific situation. and I have no desire to push the tubes to deliver an image that is brighter than I want to look at.

As for calibration, no, I'm no expert but I understand the principles quite well. And it is no crime or sin to decide that the way
I want to set up my own equipment is not an industry standard calibration. You act like it is.

The purpose is to enjoy the picture. I will, believe me.

El Duderino · Joined: 23 Jan 2011 Posts: 4653 Location: Portland, OR

“Not an industry standard calibration” isn’t a sin or crime; it’s not a ‘calibration’ either. You can adjust a volt meter to give you a more 'pleasing' or 'enjoyable' reading, but if it’s not adjusted to be in agreement with other ‘industry standard’ volt meters, or adjusted to purposefully not be in agreement, then it's miscalibrated or uncalibrated.

On the point of eye fatigue, I’d suggest the eye strain you experience is much more aggravated by your bat cave conditions than 14flL would be. Bat caves are novel, but generally not considered the best practice by many renown videophiles like Joe Kane. SMPTE also has Recommended Practice documents addressing ambient bias lighting to reduce eye strain and fatigue and how it effects things like perceived contrast performance.

**kal** · Posted: Sat May 06, 2017 8:55 pm Post subject:

napos · Joined: 21 Oct 2006 Posts: 164 Location: Athens, Greece

Chris, defocusing the blue will not make your crt blindingly bright. It will just help with the grayscale, giving you clear whites and bring the brightness of the blue channel to a similar level as the other two.
I run my brightness and contrast at 50, and am quite pleased. Daylight scenes seem realistic. To give you some sort of reference, I also have a JVC HD750 (RS20 in the US). It is rated at 900 lumens. My 9500 brightness is similar to the JVC with the iris set at -7 on low normal lamp mode.
Hope that helps you out,

Nicholas

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Again, I will investigate the effects of a slight blue defocus but I must state yet again that I am very sensitive to even small blue halos around displayed objects so I will have to evaluate for myself the effects of blue defocus and make the decision that best serves me.

Linearization of the grey scale is a desirable thing but not if it results in blue becoming excessively soft and causing me to notice visible blue halos.

There is simply no chance of me running the contrast level high enough that a fully focused blue tube can't deliver enough light output to maintain dolor balance with red and green.

So, with that in mind, the trade-off that concerns me is only gamma performance vs. blue sharpness. How much of both can I get at one time? I'll have to figure that out for myself.

napos · Joined: 21 Oct 2006 Posts: 164 Location: Athens, Greece

You wont have any problems with blue halos unless you really defocus blue too much. A defocus of about 10 units will be unnoticable as far as halos or outlines on text or objects. You also need to remenber that when defocusing the blue you want to check a test pattern with dots, to make sure the dots become "fatter" and not "donut" shaped. On my 9500 this happens when lowering the blue focus setting. It may not be the same on yours.

napos · Joined: 21 Oct 2006 Posts: 164 Location: Athens, Greece

P.S.

I am also extremelly sensitive to halos, convergence errors and color shift.

**kal** · Posted: Sun May 07, 2017 1:18 pm Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Quit rehashing it. This is getting tiresome.

This started out with me just asking for a recommendation for a calibration DISC because that is most convenient for me.

Now it has pretty much turned into a bash-fest with the bashing aimed at me.

Screw it, there's no point in asking you for any help unless I agree to do it exactly your way even though it doesn't suit my goals.

**kal** · Posted: Sun May 07, 2017 4:56 pm Post subject:

It's your condescending tone against people that are trying to help you that is very tiresome.

Example:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Let's just review what I've said before. This is all relevant.

I don't necessarily like my image set up as bright as some people do. As I've said many times, if the setup can get bright enough
that it makes me squint on bright scenes, WHY would I ever want it to be able to go brighter than that? Of course, I don't
get an answer to that question.

The blue hump exists with a blue CRT regardless of whether it's calibrated to 3 FT-L or 30 FT-L. The natural gamma curve of
the blue phosphor (and the other colors too) is clearly laid out in the CRT specification documents for all the relevant tube types,
which I have.

The reason for defocusing blue is not to level out the gamma curve, because that does not work. It is not possible. Focused or
unfocused, the blue phosphor's response is the same. But you do get more light output by defocusing as you are now allowing
the electron beam to excite more of the phosphor area rather than just a (moderately) precisely defined thin scan line. More phosphor in play, more phosphor emitting light. BTW, this is not unique to blue only, it happens with red and green, too, but we
don't care about that as they're brighter to start with.

So, we defocus blue to get more light output out of it. This is necessary if you are setting up the unit in such a way that the extra
blue light output is NEEDED for proper white balance.

But it's NOT necessary if you're not driving the tubes to such a level that the blue tube provides enough output for proper white balance while still sharply focused.

And in fact, I don't have any desire to drive the tubes so hard that I need to defocus blue to get the white balance right.

So I don't defocus blue. I don't need to. I don't need the extra brightness.

If you want to drive YOUR tubes that hard, be my guest. Absolutely no problem.

But don't insist that I need to do it your way when I'm not even after the same results that you are.

I want good white balance and maximum sharpness. You want good white balance and maximum (or at least higher) brightness.

These are two different goals that require two different approaches to achieving them.

Regardless of light output target, the blue hump still exists and has to be corrected for by applying a non-linear correction curve
to the blue drive circuit. I have various means of making those gamma adjustments, and I'll address that in due course.

racerxnet · Joined: 20 Jun 2007 Posts: 362 Location: Illinois

**kal** · Posted: Sun May 07, 2017 7:45 pm Post subject:

Yep.

I suppose you're right.

Kal

greg9518lc · Joined: 19 Apr 2016 Posts: 360

CM my 9518lc has gamma correction removed on the vim and gamma bypassed on the moome and I use
no video processor. Here is a pic of my last calibration last calibrated in October by Kurt.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I do have a Lumagen VisionPro HDP scaler which is not installed in my system, but it does offer 11 point gamma correction.

The catch is, its digital connections are DVI and it's limited to 1080i input. Currently I'm running 1080p direct from BD player to Moome input card and it's all on HDMI. So switching over to the Lumagen unit will be a compromise.

But I'm already dealing with a compromise, so all I'm doing if I switch over is choosing which compromise I want to accept.

I suppose I could get some HDMI to DVI cables and give it a test run. I know the player can output 1080i.

But then I have to figure out if I'd get a better image from 1080i or 720p input.

It'd be easier if I had a more modern processor that passes 1080p thru on HDMI, But I don't have that and don't really
have the budget for any NEW equipment right now.

greg9518lc · Joined: 19 Apr 2016 Posts: 360

You have your vim and moome bypassed? There is not enough to be gained with
a processor especially the dvi unit.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

My current setup is Blu-Ray player to Moome HDMI and that is the total signal path.

Well, there is an HDMI 1 in, 2 out splitter that also just happens to remove HDCP, but that's not really a signal processor
in any visual sense.

Using the Lumagen does allow me to adjust front porch timings to get rid of that rather pronounced ringing that has always
been something I've had to live with with the current setup. It also gives me that 11 point gamma correction.

Better yet I should save up for something more modern and more capable.

greg9518lc · Joined: 19 Apr 2016 Posts: 360

The question is have you bypassed the vim and moone this will ve your cheapest and biggest gain not spending money.Also you can push out almost all of thebringing with setup.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

No, I'm working with dead stock Marquees at the moment, but using the Moome HDMI input.