CurtPalme.com Home Theater Forum

[Lar407]

I'm running a NEC XG750 using original HD Fury connected via 15 foot HDMI cable to a Panasonic BD-55. I can get 1080i resolution without any problems, but 1080P results in banding and rolling bands of scan lines when the video is in motion. Does anyone know a fix for this, or is 1080P just too much for a NEC XG750?

[MikeEby]

The standard sync timings out of a Blu-ray player are not compatible with an XG. You need to either use a scaler or an HTPC and setup custom timings to get 1080 to sync correctly. BTW even when you do get it to display properly the image will likely be a bit soft because the video bandwidth required for 1080p is really to high for an XG.

Mike

[Lar407]

Hey Mike, thanks for the input about the limitations of NEC's XG series projectors. I originally suspected my blue ray player's capability as the culprit because my projector can display a nice 1080P@60 image that's static. The disturbance of horizontal banding "noise" starts only when the action appears. You said that an outboard HD scaler or PC could get 1080P to sync properly but the image would be softer because the bandwidth required for 1080P is too high for an XG projector. Can you tell me what bandwidth is required for 1080P?

Thanks again.

[MikeEby]

I think 1080p@60hz requires around 150Mhz of video bandwidth to properly resolve. That doesn't mean you can't get a decent picture if your projector cannot fully resolve the image, the picture will just show some softness. Many people with XG's and PC's run 1080i96Hz. I use 1600X900p @72Hz with my XG and HTPC.

Mike

[Lar407]

I will be investing some time to run an additional feed from my P/C to the projector. Once the wiring is in place I can test the signals you suggested to see if they look better than the 1080i 60Hz signal I'm currently using via direct feed from my blue ray player.

Thanks again for clarifying this, you have been very helpful.

[Jesse S]

[MikeEby]

[bbgh35]

HI, I have a problem with the blanket statement that " the video bandwidth required for 1080p is really to high for an XG". Mike is correct regarding your XG750's bandwidth limitations and difficulty with 1080P, the only solution for all XG's is an outboard processor that allows porch adjustment's or a HTPC. There are other XG models however that do have higher bandwidths and while some factory calibrated XG's might exhibit the softness Mike describes, a properly calibrated XG110 or XG135 can be razor sharp with 1080P.

[Lar407]

Hey bbgh35, Thanks for the additional input. In checking specs on NEC XG's I see that my 75 model has a video bandwidth of 100MHz while the 110 and 135models have 120MHz. I'm not prepared to chuck my model for an upgrade to 110 or 135. I don't have any objection to the 1080i@60 image that my XG75 resolves. That having been said, it's not 1080P, so, if I can eek out an improvement without too much fuss or expense I'm interested. I'm currently running a video & audio lead through my attic from my P/C location to the projector which is in my Family Room. Once this is done I can fool around with the settings to see what's possible.

I appreciate the input guys. If you have any other suggestions please join in.

[Spanky Ham]

I am not going to get into this as this topic has been covered many times. The specs are mostly inflated BS. The bandwidth required for 1080p60, I believe, is around 65 or 70. Extron multiplied it by 3 and that number has stuck. CRT doesn't have great MTF to begin with. At the end of the day, your best bet is to try out different resolutions and see which one or ones you prefer.

[Lar407]

Spanky Ham, I don't know enough about video bandwidth to comment one way or another. All I wanted to know whether or not I could tweek a higher resolution than 1080i on my NEC XG75. Mike suggests 1080i96Hz or 1600X900p@76 Hz. I don't have these options on my N-Vidia Quadro Graphics Card driver.

[MikeEby]

[Mark_A_W]

Well, the xxx0 models are quite different to the xxx1 and xxx2 models.


So in theory there are two different bandwidth levels.


But in practice they look much the same to me (never seen an xxx2 model though).


And IMO, if you think an XG is razor sharp at 1080p, then you haven't seen a 909 (or a digital..). An XG is ok at these res's, but not great - other stuff about the image is fantastic, such as the black level, but the sharpness is just "ok".



Lar, you'll need to use the Nvidia custom resolution tool.

[Lar407]

Ok. Thanks. I'll check the custom res tool. I completely overlooked that option.

[Lar407]

Hey Mark, no doubt that a 909 performance beats and XG but don't you think that comparing an Intermediate Level PJ to a High Performance Level PJ is like comparing apples to oranges?

[Mark_A_W]

It was more of a response to this comment:

"properly calibrated XG110 or XG135 can be razor sharp with 1080P."


I disagree.

They are "ok". Not razor sharp.

And there's not difference between models, only generations (and LC vs AC). All models in the same generation use the same hardware.

[Lar407]

Okay, I get it. I guess it's how you interpreted the comment. Since I'm trying to go better than 1080i on my XG, I was interpreting the comment as meaning razor compared to 1080i on an XG. Anyhow, I finally ran the video/audio connections from the P/C in my Home Office to hook up to the Projector in my Family Room . So far every other resolution I have tried is softer than what I'm getting through my BD-55 via 1080i. Some are not usable because the shift to left from Fury 1 is just too much to center simultaneously on my LCD monitor( which I need for P/C Control). I have to find a setting that will center equally as well on my LCD Samsung MultiSync monitor as it will on my NEC XG Projector.

[Spanky Ham]

To add to what Mark said, I believe we measured the MTF of a VDC 9500 at around 30 or so. It really didn't budge much until the res was dropped to like 800x600 or 1024x768 IIRC. To put that in perspective, I think a single chip DLP is above 80 from what I have read. I plan (I know I have said it a couple of times now but I really mean it this time:)) on stopping by VDC in two weeks and checking out the new LED pj. Hopefully I can take some measurements while I am there.

Oh and I don't want to start an argument, but no amount of mods from MP or anyone else are going to raise that MTF significantly. CRT is what it is and razor sharpness isn't one of its attributes.

[Lar407]

Looks like this thread has escalated far beyond my scope . I'm bowing out. I think you guys have given me enough input to do the best I can within the limitations of my XG CRT. I appreciate it. Thanks again to all.

[Mark_A_W]

Lar

1080/30i will be about the sharpest you can get.

But the field lines can be objectionable, and you get motion judder.

I run 1080/48i (we refer to it as 1080i 96hz usually - it's just semantics), which won't be quite as sharp, but it will be more solid, and you can get smooth motion.

You'd need to use the Nvidia custom res tool to try this, and you'll need to know that you use 540 instead of 1080 as the number of lines....hell, you need a tutorial, it's not easy..