Lumagen HDP- owners' help please!!

[usman24]

I purchased a Lumagen HDP a few months ago and had this isf calibrated. initially I complained to my retailer that the vertical line [to check that it is pixel mapped] in-built lumagen pattern is producing an awful lot of noise/flickering very similar too severe interference all over the screen. Horizontal pattern looks stable.

I was told to adjust phase on the panel until it dissappears and it did. Problem was that you had to adjust this to hide the flickering/line noise with every change of program material. Than i tried reducing sharpness to -11, this helped by hiding the noise on the pattern, but was not not sorting out he root cause.

Now, recently I have noticed that the scaler is introducing the same flickering noise on real program material i.e dvd's etc. I noticed this on a fairly dark scene in LOTR fellowship and the artifact was obvious and i paused the scene and set my dvd player to progressive and the noise reduced considerably but the v- pattern remained very noisy on both ntsc and pal.

Can any other owners please check your in-built vertical resolution pattern the see if you have the same issue and let me know what you find?

I think the scaler's scaling output maybe faulty?

Any help/advice would be appreciated.

[Neil Davidson]

It is almost certianly the PH9 rather than the scaler.

For some reason the timings needed to get 1:1 mapping working cleanly are quite a ways from the VESA standard timings (on the 42PH9).

I have never spent time with the 50PH9 to work out it's optimal timings though.

For reference could the noise be described as several vertical bands each with wide fuzzy horizontal lines across it? It should move as you adjust the phase/sharpness controls?

[usman24]

Thanks for your reply.

I would say it is more like severe noise all over the v-pattern that looks like horizontal line twitter/electrical type noise with other bits of random noise all over the screen? Are you sure its not a power supply fault through the lumagen power converter/adaptor or faulty scaling output?

When I looked at the same scenes without the scaler there is no more electrial type interference and its looks far more stable.

[Neil Davidson]

Hi,

Without seeing it I can't be sure but I would say 98% that it is the panel. I think there was even a thread here discusiing a VP50 showing the same effects.

It is a timing issue related to getting perfect 1:1 pixel map which I would guess is not possible from other sources which would be scaled internally resulting in no noise (as no timing issue)

[Liam @ Prog AV]

It sounds to me like the panel getting in the way which is revealing itself more through the test patterns than the material. You mention you have started seeing it in material, but I don't think this would be on account of it somehow getting worse. Just that you are seeing it more now that you've had this combo most of the year.

It just isn't possible for a power supply to do this, or for just the scaling portion of the VP to suddenly decide to put noise in. The Lumagen really doesn't work like that. Since Gordon has ISFd the screen for you to I can be more than confident that it has been seen by someone who knows what maximum PQ is possible and whether it is doing it or not. The problem is that there is no such thing as a 100% perfect picture, you change one thing for one artefact and introduce another!!! The absolute best trade off will always be a trade off I'm afraid. I'm not sure if the PH9 was affected, but I remember seeing reports of the PH10 simply no longer to 1:1 perfectly with 50Hz from analogue. As soon as you adjusted SIZE/POS and set your sharpness, colour and greyscales the processing in the screen would re-process in some way. It is totally unavoidable. Do you see this same problem as severely with 60Hz??? Take care in playing around with your settings since having it ISFd, I doubt you with your own eyes can be better than a career specialist with several grands worth of measuring tools!!!! Sharpness for example will add/remove edge enhancement which can directly affect this kind of pattern. I'm not sure I would want to play around with something that has already been calibrated!!!!!

[Gordon @ Convergent AV]

I can add that I have emailed Usman and I am working towards isolating the issue. Usman, I have to go out for most of today but I think that there may be a post by someone on the Lumagen support forum who had the same effect on screen but who managed to come up with some weird timings that minimised the issue. I will attempt to find this information when I get a moment.

I will pass this on via email in the first instance.

Gordon

[Neil Davidson]

On the 42PH9 you can erradicate it completely but the timings are really wierd!

In the end I resorted to using power strip and my PC to find them.

[usman24]

unfortunately Liam, I have also noticed the same effect on an ntsc disc yesterday. I will await any further advice from Gordon.

[usman24]

This might sound a bit strange but could I try setting the lumagen to 720p output or 1080p output and either let the panel scale up to 768p or downscale to 768p from 1080p? Would this in theory eliminate the flickering/horizontal line picture noise?
Rather than attempting to pixel map to the panel? If this would solve the problem how to I set it to either of the above settings [720p/1080p]?

[Liam @ Prog AV]

It will give you *different* scaling artefacts which may or not be preferable to your eyes overall.

You will be losing your ISF settings though.

[usman24]

would changing the output settings lose all ISF colour/contrast/brightness gamma settings? Or just overscan?

[Liam @ Prog AV]

You will be presenting the TV with a different resolution, so all the settings stored in the TV will be changed/bypassed. The knock on effect is that everything is affected to one degree or another.

[Gordon @ Convergent AV]

Actually with the Panasonic commercial panels the effect on calibration may not be that grea swapping between some video resolutions. Alot of the service greyscale stuff for video source signals is tied together. I can't remember if the xga memory is affected by video res greyscale changes.

Gordon

[usman24]

The other alternative is adjusting clock phase with every viewing session to reduce the noise levels although its not an ideal solution. Unless there are some custom settings for pixel mapping to get rid of the problem once and for all and setting overscan via the panels' service menu is fairly straight forward?

I will try 720p/1080p output if I can find some presets. Also for some weird reason 60hz pattern is producing the same noise on v-pattern same as 50 hz, this should be noise free i.e true pixel mapped?

Pioneer LX508 here I come hahaha!!