AVS Forum banner
Status
Not open for further replies.
1 - 20 of 62 Posts

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #1 ·
I have finally sorted out the Phelps Optimization process for the JVC SX-21. JVC did some interesting things with this projector; it took a while to figure out how to deal with it.


What can you expect if you decide to have this done?


1) Color accuracy - out of the box the projector appears calibrated to near 6500K, but the colors will be off - whites will look more like cyan. Why? Because color temperature can be "tricked"! All color analyzers report Correlated Color Temperature (CCT), and that first word is the key here. It is possible to adjust for more light ouput by adding green and blue, and still have the CCT be 6500. However, this is not D65, which is what we really want. D65 is the specification for the x & y coordinates of white (0.313, 0.329 in CIE 1931 coordinates). Unlike CCT it cannot be "tricked". This is what I adjust the projector for, and the difference is dramatic.


2) Contrast ratio - this will probably be reduced somewhat from the out of the box value. Typical numbers I'm getting are in the high 600's to low 700's after calibration. I am finding that most SX-21's will need a CC (Color Correction) filter to get both good C/R and better (lower) black level. This does mean some reduction in total light output.

Added: The above applies to the DVI input only. For those of you using RGB or Component, you are going to be really happy - the C/R will go from around 450 to 650 or better!


3) Improved luminance curve (the projector's gamma characteristic). The graphs I've included here show the difference. Out of the box the SX-21 is better than any of the earlier JVC D-ILA's, but it's still a bit off. I recalibrate to what is my now standard "reference quality" gamma curve. The visible difference is that the picture will appear to have better contrast.


4) Blue "cast" at very low levels - I am not able to fix this completely, this projector does go blue at the bottom (below 10 IRE). The CC filter does help this some, but to fix it completely would require so much filter that the light output would be reduced too much.


5) Internal "gamma" LUT's - very signifcant changes here, which result in a noticeable improvement in low level detail and reduction of "posterization" artifacts.


Notes on the graphs:


CCT: the plot of Correlated Color Temperature


D65 Error: a plot I invented (patent applied for) that shows the distance from the ideal x,y coordinates (D65), scaled and inverted so that it mirrors the CCT line.


When CCT and "D65 Error" meet, the color (of white) is perfect.


Here are the graphs for a typical SX-21:


Before: http://www.meier-phelps.com/sx21/sx2...le1.before.jpg

After: http://www.meier-phelps.com/sx21/sx21.sample1.pass3.jpg


The reference instrument for all Optimizations is a Gretag LightSpex, accurate to +/- 0.001 (CIE 1931 x,y), traceable to N.I.S.T., and recertified annually (at a cost that exceeds many color analyzers).


William
 

·
Registered
Joined
·
9,769 Posts
Great news wm! except at the expense of CR:( and of course brightness.
 

·
Registered
Joined
·
23,188 Posts
Great to hear about this William. I asked this on another thread, but if we see any kind of fixed pattern noise can you do anything to adjust that?


Thanks,

Darin
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #5 ·
Quote:
Originally posted by darinp2
Great to hear about this William. I asked this on another thread, but if we see any kind of fixed pattern noise can you do anything to adjust that?
Darin,


Not sure, but it's possible. The way I redo the projector's LUT's might help with this. If you have a way to test this please email me about it.


William
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #6 ·
Quote:
Originally posted by Tryg
Great news wm! except at the expense of CR:( and of course brightness.
Tryg,


The CR dropped from 779 to 704 on the example I posted. I doubt you'd see it. What you will see is an improvement in apparent contrast because of the change in the luminance (gamma) curve.


Yes, the overall light output goes down significantly. If you really need all of the light that the projector is capable of, and can live with the color (in)accuracy of the stock projector, then don't have it calibrated! Note that the light output of a calibrated SX-21 with a CC15R filter is about 50% more than a Sony G90...


William
 

·
Registered
Joined
·
39 Posts
As a new SX-21 owner, what original equipment manufacture of CC filters do you recommend ?


The CC filter seems like a valuable addition just as an anamorph lens.



thanks in advance.....





mark
 

·
Premium Member
Joined
·
688 Posts
William,


A few questions:


1) How do you feel the calibrated SX21 compares to a calibrated G15?

2) Where does someone mount the filter on the SX21, do you have any idea if it will interfere with mounting a panamorph?

3) I hopefully will receive my SX21 next week. I believe on the G15 you generally preferred the user had burned them in for about 50 hrs before shipping to you for calibration, if my recollection is correct do you want the samething for SX21?

4) Do you provide the filter or do I need to get that before shipping the projector to you?


Thank you

Bryan
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #9 ·
Mark (Stormy),


I provide the CC filter as part of the service. The specific value is determined during the calibration.


William
 

·
Registered
Joined
·
1,363 Posts
William


Hi again from New York.


I am signed up to be Phelped next week - does it hurt?


Can you let me know by email the exact date and i'll drive down with the PJ and lens.


Rob
 

·
Registered
Joined
·
3 Posts
William,


I've recently purchased an SX-21 with a Grayhawk 92 in diagonal screen. I plan to use an ISCO II lens projecting from a distance of 12 feet. (I have a very small room). Though some have recommended a Firehawk screen, I chose to go with the Grayhawk, because I felt that the combination of screen size and anamorphic lens would still provide plenty of "punch" to the image, and increase contrast. With calibration and the CC filter, would this decrease the light output to the extent that I might want to consider a higher gain screen. My room is partially light controlled. Thanks in advance


Ron C.
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #12 ·
Ron,

I would go with the Firehawk, at least partially because I like it better, and because of the light output.

William
 

·
Registered
Joined
·
144 Posts
As someone who wants to buy the projector, hook it up tinker with it some and then leave it alone this stuff is scary. William, will this projector work in a dark room with a 150"" firehawk. I do not want to spend another $10000 on bolt-ons.
 

·
Registered
Joined
·
449 Posts
William,

I am interested that the sx21 has 780 compared to JVC stated 800 but calibrates down to 704.

Yet in your opening post for component you say 450 to 650 or higher calibrated.

What Ansi lumen brightess was the 780 measured -and at what was the 450 measured?

There seems too be some contradiction here.
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #15 ·
apopple: Ron asked for my opinion and I gave it, but it's just that, an opinion. What "works" for one person might not work for you, only you can decide what works for you. I understand it's not an easy decision.

William
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #16 ·
HEAT:


No contradictions. The component input is analog and goes thru a different stage in the projector, as does the RGB input (same connectors, actually, on this pj).


I can easily get over 800:1 out of the projector but not with white at D65. If you don't care about accurate color run it "out of the box".


I have not reported on ANSI lumens for the SX-21.


William
 

·
Registered
Joined
·
1,363 Posts
Quote:
Originally posted by apopple
As someone who wants to buy the projector, hook it up tinker with it some and then leave it alone this stuff is scary. William, will this projector work in a dark room with a 150"" firehawk. I do not want to spend another $10000 on bolt-ons.
The SX21 provides the best digital PJ image i have ever seen. That is before William's calibration.


It will "work" fine with a Firehawk.


What you are seeing here and on other threads is people trying to "optimize" performance of their equipment through tweaks and combining best parts.


That is quite normal with any hobby.


If you want to get really freaked out, check out the screen area and see the thread from tryg about the Silverstar. That is reallt scary :)


Rob
 

·
Registered
Joined
·
144 Posts
Okay, "work" may not have been the proper word. How about a sharp, bright, film-like picture @ 150 inches 1.33 or 1.78. Question #2: If you only had $6,000 to spend on a PJ and wanted to use a 150" screen, which PJ and screen would you buy (the $6,000 is for the PJ). Use the desired outcomes I listed. Thanks :)

Andy P
 

·
Registered
Joined
·
2,293 Posts
Discussion Starter · #19 ·
Andy,

I don't think this thread is the appropriate place for your question. This is really intended to be a discussion of (or more the announcement of) the availability of my Optimization service for the JVC SX-21.

Thanks,

William
 

·
Premium Member
Joined
·
16,978 Posts
Andy


Not to bypass your question but the topic of this thread is for the SX-21 Optimization.


I would post your question to the 5k + forum. Be prepared, if you get 10 responses you will get 10 different answers.

What works for others may not work for you. Seeing as your being cautious I would not take anyones advise. You should go see as many set ups possible and see what looks attractive to your taste.

If you do not have a local retailer in your area do a post to see what forum members are in your area & willing to share their system with you.


I dont think any knowledgeable person will suggest a system and give you their guaranty it will work for you. Thats impossible.
 
1 - 20 of 62 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Status
Not open for further replies.
Top