CurtPalme.com Home Theater Forum

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

I've had this problem since day one with my G70. It wasn't much of a big deal to me until recently when I got my raster perfectly centered on the tube face and no longer want to tip toe around it by adjusting my throw or my raster position off center to compensate.
On each tube there is a straight bold line and a much fainter arched thin line at the top of the raster. It appears whether a source is connected or not. On screen only the bold line is visible as a faint grey line at the top of the image. If I move the active image area into this line it cuts the image off and any scan lines that pass it end up on the bottom of the screen. In contrast to my well centered raster, the active image wants to show up well above center. I have to adjust RGB shift all the way down to get it close to the center of the screen. The only way i know of to get RGB shift close to mid range would be to throw my raster off center or adjust my projection angle and i would rather not do either.
Here are a few pictures. Does anyone know what this is?

ecrabb · Posted: Sat Jan 30, 2010 10:20 pm Post subject:

Yep, that's the AKB line (Sony calls it ABG).

There are lots of references to it in many threads, including some posts by me.

Here's the one thread I could find quickly - lots of info:
https://www.curtpalme.com/forum_archived/viewtopic.php@t=10881.html

SC

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Thanks ecrabb. That was indeed very informative. What did you end up doing with your setup once everything was all said and done? It sounded like you were at the same place then that i am now. My hunch is that this whole raster maximizing philosophy that i've heard so much about is not serving me very well. Just like you i am dealing with the ringing issue and the AKB line and i might be having trouble with raster wrap as well but i'm not 100% sure on that last one as it is a new term to me.
I plan on getting a calibration setup soon anyway so I think I can probably get away with having ABG off.
I have a 78" 1.50:1 screen that gives me a 75" diagonal in 16:9 I just set the throw 3" further back to 85" and i have the raster maxed but it still only overshoots the sides of the screen by half an inch or so. What do you think?
Anyway, I'm going to set AGB off and report back.

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Ok, SO turning ABG off got rid of the lines and made the picture markedly dimmer, but this did nothing for the RGB Shift adjustment issue. The image will still clip if it is adjusted up to where the AKB line was and it is still no where near centered without adjusting RGB Shift all the way down. I also realized that since I have my projection angle on a zero axis (parallel with the floor), increasing the throw distance won't make any difference on the position of the center of the image. It will stay constant. I just don't understand why the image wants to be so high up!
Here is the video chain: PS3 on component - RTC2200 - G70 through RGBHV running 1080i. I backed off all the turnpots on the RTC2200 but there was no effect.
Any Ideas?

AFryia · Posted: Sun Jan 31, 2010 1:46 am Post subject:

I run with AGB On and rarely notice it watching video. Video is more stable IMO.

First question what resolutions are you trying to run? In my experience 1280x720p 60/72hz I can pretty much use standard video timings (HTPC/PowerStrip) and get things centered with raster maximized. 1080i I think my timings are standard also.

At higher resolutions (bandwidth) I also have centering issues. The counter measure is to increase the porch sizes in PowerStrip.

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

I'm not running an HTPC. I've heard porch sizes help with ringing a well. I assume all of my timings would be considered standard since i'm using a PS3 as my source. I run 1080i (60Hz?) almost exclusively.
Maybe moving the raster down and off center is the best soultion for this problem. If I increase the throw distance another two inches or so and then lower the raster down a little I might have enough wiggle room to bring the image down a few more clicks or up a little with out hitting the AKB line. That way if a different source shifts it off center i would have room for adjustment. I would still be at the very low end of the RGB Shift Adjustment, making it an imperfect solution, but at least I wouldn't need a scaler or an HTPC. It does sound like a PC or a Scaler can make life a lot easier though...

CIR Engineering · Posted: Sun Jan 31, 2010 3:27 pm Post subject:

Don't center the image inside the raster. Center the image on the tube face, but have the image at the lower right porting of the raster (when looking on the screen). This way you will avoid raster ringing and probably the other problems you are having.

Use the "center" function to move the raster. Then use the "shift" function to move the image inside the raster.

Use "shift" to push the image to the bottom right of the raster, but be careful. You will find a point when you move the image too far to the right side (and the bottom side) and the image will start to compress. When the image starts to compress move the "shift" back to the left by two or three clicks at the bottom and top. The easiest way to see compression is with a circle hatch pattern with circles in the corners, but a hatch pattern works well also.

So start by shifting the image to the lower right of the raster with shift. And then just center the image on the tube face (screen) with the center function. Don't worry if the raster goes off the tube face on the left side (of the screen) as long as the image stays on the phosphor.

After that, set your blanking right up the the edge of the image on all four sides.

craigr

CIR Engineering · Posted: Sun Jan 31, 2010 3:34 pm Post subject:

**Curt Palme** · Posted: Sun Jan 31, 2010 6:20 pm Post subject:

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Thanks Craig, that makes perfect sense! I guess I just wasn't thinking "outside of the box" literally! I remember you mentioning something in another thread about this but I completely misunderstood your meaning.
Please rest assured that I plan on having you calibrate my setup when the time comes. I just want to get a basic calibration setup to play with and maybe make a niche for myself at the AV store I work at. The only guys doing calibration in this town is Best Buy and I think I might be able to do better than them. Part of my motivation for getting you to calibrate my setup is to have a reference display from a real pro. Once I have the prints finished I can send you a copy to make sure my setup is easy for you to work with. I still have to hang the unit and mirrors and get a scaler and an HDMI card. So it will still be a while before it will be ready.

CIR Engineering · Posted: Mon Feb 01, 2010 2:42 pm Post subject:

CIR Engineering · Posted: Mon Feb 01, 2010 2:46 pm Post subject:

Hey, I just edited my post above because I had my lefts and rights backwards in some places. I hadn't finished my coffee yet when I posted those instructions.... but I haven't finished my coffee yet this morning either so watch out!

craigr

CIR Engineering · Posted: Mon Feb 01, 2010 2:49 pm Post subject:

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

CIR Engineering · Posted: Sat Feb 20, 2010 10:00 pm Post subject:

Nice work.

However you are still doing something wrong. The throw distance has nothing to do with the raster ringing or image position. Position the projector to maximize your phosphor usage as you had done in the past. Then just use the center adjustment to put the image in center.

The size adjustment increases both the image and raster sizes together. So if you increase the width the image should stay the same distance from all sides of the raster and you should not get any more or less raster ringing no matter where the projector is positioned.

Am I making sense?

craigr

CIR Engineering · Posted: Sat Feb 20, 2010 10:02 pm Post subject:

Maximizing the phosphor usage on 8" machines like the G70 is absolutely critical so you must do this right. A g70 can come close to fully resolving 1080p 60Hz if you set up your image to use the entire tube face. Ever millimeter of wasted tube face will result in loss of resolution and you don't want that Wink

craigr

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Ok, If i understand you correctly I can put the throw back up to the 82" which i used initially. With size and raster maxed out I had a 1080i active image area almost touch the tube face sides (equal to or less than 1/8" clearance) and just barely fill the screen with about a 1/2 inch of adjustment to spare. I had trouble with 720p filling the screen, as you may recall, but that is what the VP can help with, I suppose. Then all i have to do is move my raster off center and adjust the shift setting to recenter the image and perform a few geometry corrections to get a nice ringing free picture? I think i'll start moving my screen back right now.

Thanks!