CurtPalme.com Home Theater Forum

[ecrabb]

[Clarence]

[ecrabb]

AAARRRRGGGGGHHHHHHHH.... I found it. It was right there in the menu. Apparently, the 31st time I looked at the menu, it magically appeared, because I'm certain it wasn't there the other 30 times I was in there.

Thanks, "Searchmaster" Clarence. I looked for hours one night and never stumbled onto that thread. Good to know. Now, I know I don't need the newer firmware. The only thing I think I'm missing from the newer firmware is the better memory management with block copying (which would be nice).

But, PROBLEM SOLVED. ABG off, and the Dave Matthews BD that flickered like hell is now perfect. No sh*t, greyscale has to be redone. I had to jack up G2 because until I did, I had no light on the screen even with brightness jacked to MAX. Regardless, I have no more AKB line and I'm happy as a pig in...

Brian, I got the News doodad turned off on the PS3. I was suffering from the same "can't see sh*t" syndrom that I had looking at the G70 service menu. I kept looking in system preferences (imagine that) instead of that damn "network" item on the XMB.

Thanks Brian, Clarence, and everybody. God, I love this forum... Oh, and my G70, too.

Sorry to highjack your thread, Rob. Now, back to your regularly scheduled programming.

SC

[Bitwize]

[ecrabb]

I don't have a line on the left, but I do have some ringing in brighter content on about the left 10% of the screen. There's a little geometric distortion I need to take out of that area, too. I can't remember who it is here that I got the recommendation from, but setting up with the internal test pattern hanging way off the screen. I'll see if I can snap a pic so you can see where my test pattern lands... Once I set it up that way, I didn' have any trouble with the line or wrapping on the left.

I'm using an HD Fury, not the Moome card, so there could be a difference there.

I'm using a WilsonArt screen (96x54), and uniformity is pretty good. I don't notice the hot-spotting much except on primarily solid and high APL material, so uniformity is pretty good. I'll see if I can take a pic of the hotspotting and subtle color shift.

SC

PS - I have the stock lense, just like everybody else... except for YOU!!!

[Bitwize]

[ecrabb]

Oh, you have a Carada 1.4. Dave (person99) made me aware of some tests that showed that screen to be closer to 1.1 - which is probably why you're not getting any hot-spotting. That's probably pretty close the same gain as my laminate. What size screen are you running? I rarely see any color shift - obviously only on whites or neutral colors, and it isn't bad. Uniformity could be better, but CRT will never be "good digital" good in that department. There's just too much fall-off with these lenses - the lenses would have to be massive to eliminate it. In fact, now that I think about it, the VR lenses on your machine may sacrifice some uniformity in favor of more sharpness, possibly by way of a slightly smaller overall aperture. Not sure about that, hough.

I'm just running an HD Fury right now. I'd love to try a new Moome card, but I just can't bring myself to drop the coin right now. Maybe this fall or something. I'm sure it will be a step up in image quality from the HD Fury, matrix switcher, and 25 feet of analog cable I'm using.

I'll try to snap a few pics this weekend and we can compare notes.

Cheers,
SC

[r.bauer]

The ABG should really be turned on when using a G70, or else you will have te recalibrate every other night. Also sometimes you are not able to achive maximum lightoutput. ABG should only be turned off when adjusting G2. (If your G70 has that option available. And set bias and gain to factory settings prior to adjusting the G2)

Brightness fluctuations during movies are often related a to wrong vertical shift position. In such a case the internal blacklevel is set to a wrong level. Ever so slightly adjusting Vertical shift solves this problem instantly.

Although the control of brightness- and colorpurity seems to be very rudimental, they do a very good job! Read the proper manual to find the proper setting. Also the screen selection in the G70 has a huge effect on this, this must also be properly set, see manual for the right choice. These three settings can really throw off a G70.

Check your screen for color-shift. Stand 1 meter behind the projector and move 1-1.5 meter to the left from the center and move 1-1.5 meters to the right from center. Does the color-shift move with you? If so, the screen is the cause of it.

If you still think the tubes are your main cause, check them individually with a full Red, Green or Blue.
You can check if it is either a mis-setting of brightness- or colorpurity or screen selection by reversing the H- and V-scan swithces/cables. See if the color shift is the same or it has moved with the switches/connectors.

The G70 is a VERY, VERY nice projector and throws an outstanding image. Enjoy it a lot!

[Brian Hampton]

Whenever I tried to adjust the uniformity seemed like nothing happened as I went through the entire range.

??

I can sort of see your point about having AKB on because to a certain extent AKB seems to work really well. I can mask the line up top with ease but then there is a u shaped line that always dips down into the image area and I can't live with that.

Many popular projectors like the Marquee have no such function as AKB and don't seem to be re-calibrated every other night.

Still... I went back and forth quite a bit with AKB both on my early 1271 and my G70.


=Brian

[ecrabb]

Thanks, r.bauer. But, what about the obnoxious AKB line? It's REALLY distracting, and kind of destroys what is otherwise a really nice artifact-free image. A big, green, dim, ovular line hanging a couple inches down into the screen and splashing on the wall behind doesn't really trip my trigger so to speak. Bleh.

As for the brightness fluctuation, I'd read about the V-shift, and did try that to no avail (perhaps it was like my ABG menu option, though!). I'll have to see what another (different) setup does for the situation. I do know it's only a problem with 1080p - I don't have the issue any other res, and it doesn't even happen with all source material (though all on the PS3 as the source) - which is interesting to me.

I'm wondering, though. Why would turning off ABG require any more frequent calibration than any other projector? You're kind of implying that the G70's G2 settings aren't stable without ABG enabled... which would kind of surprise me. From the little reading I've done, it seems the ABG circuit is to make G2 (and in effect grayscale) even more stable via its ability to counteract environmental conditions and aging CRTs. Given how we use these machines (temp controlled, light-duty, low hours), it doesn't seem necessary. The G70 brochure says this:

[r.bauer]

The ABG line usually falls on the black (velvet or something similar) border of the screen and so it is practically invisible. If you find it disturbing, you have to make a choice, but only if you can and wil calibrate regularly (and properly!)

How quickly the greyscale changes, I don't know exactly, but a projector that that has no stabilized G2 can dritft easily and quickly out of calibration as each tube will drift differently! And the human eye is far more sensistive to minute color changes as compared to brightness (read: contrast) changes. Also remember that these projectors were designed and built to go on and on and on whithout any service and still give a wonderfull picture after 10.000 hours. This is simply not possible whithout an ABG circuit.

I will not comment to much on the marquee projectors having no ABG, but a G70 is a far, far more complex projector compared to a Marquee. Lets just say I like the G70 a lot more. 8)

In planetariums absolute black is a must have, so no compromise there. (I have seen an 8 CRT-projector planetarium using a 20 meter diameter dome, and it was awesome thanks to its absolute blacklevel.)

Are you using a HDfury on 1080p? It requires a (hefty) power supply, as it quite power hungry at these high resolutions! Feel how hot a HDfury gets at these resolutions. Maybe this has something to do with the fluctuating brightness.

Unfortunately not all CRT-projectors are used in climate controlled HT's, so drift is really an issue out there with end-users.

[overclkr]

Just so you guys know, the ABG/AKB line SHOULD NOT protrude into your used raster. If it does, the projector is not set up properly.

I did turn this feature off in my original G70 because Ken had access to G2. If your tubes have been changed, I STRONGLY advise you leave it on.

Also, I suspect this "flickering" is due to poor setup IE the ABG/AKB line is protruding into the used raster. If you can see it on your screen, your setup is not right.

Cliff

[ecrabb]

OK, that's good to know, Cliff. Because, after I turned off ABG, and cranked up G2 to get good shadow detail back, now the ABG line is showing up again (although not nearly as bright as when ABG is on. That tells me you're right about bad setup. I think I'll do full setup again, then.

Assuming what you say is true about ABG not being in the active image area (I trust you, big dog!!!), then that means you have to do geometry on the internal pattern with the borders extending WAY beyond the 16:9 screen, yes? As in, a foot above and below - at least?

The first time I did it, I set it up so the internal pattern (raster, yes?) went to the edges of the screen. That was totally unusable with 1080p. Totally. All sorts of trouble - raster wrap, ringing, distortion, etc. So, the second time, I set it up with the second grid line hitting the edge of the screen on top/bottom, and the first box about half off the sides. That gives almost acceptable 1080p performance. Set up like that, I just have a little ringing on the left side and some wavy geometry.

Obviously, I need to do it again, but with way more off the sides of the screen. What a pain, though - won't all my outside zones be completely off the screen? How do you even set it up right with the image hanging a foot off the screen - on a black wall, no less. Maybe I don't get something. I'll take any advice I can get at this point. I'm learning.

I do have optical focus and scheimpflug NAILED, though. Using the Guy Kuo 'index card' method, I think the focus plane might be slightly in front of the screen. It's so close it's REALLY hard to tell. The phosphor grain is sharper than the image, which means I probably have some EM work to do - maybe. It's damn good, though. It just completely DESTROYS the image I used to get out of the old 1271. I'm so excited. It already looks AWESOME and I have quite a ways to go.

I attached a pic of the center of the SMPTE pattern I said I'd snap.

SC

[overclkr]

[Brian Hampton]

I went a experimented with ABG or AKB or whatever this AM.

I must say the ABG function does seem to work very well. It certainly seems to change the gamma curve or overall contrast ratio. But,.. I don't think having it on works for me.

With Bias, Gain, Brightness, and Contrast I've got all the controls I need to make the picture great and I don't have the AKB line or the bowing U shaped line or anything like that.

My screen is small and my room is pitch black. I don't think I'm significantly "age-ing" my tubes over the course of watching a movie.

I have been flippant about AKB in the past as I see it does have certain perceived advantages but for now I'm leaving mine off.

(I'll be interested to read about other G70's and results per usual.)

-Brian

[Bitwize]

[overclkr]

what you guys will notice over time if you leave it off, that your G2 will not automatically adjust as your tubes age.

The cool thing about ABG for me on the G90 is it turns off (the line and bow) 15 minutes after you start the projector.

Leaving it off for 6 months and then turning it on for a session of about 5 minutes will then cause the projector to automatically feed your tubes the right G2 values. Then simply turn it back off, recalibrate, and your good for another 6 months.

This is how I've been doing it for years now. Even on an XG it is useful.

Cliff

[Brian Hampton]

Hey,

The G90 certainly has the prime way of doing it.

Just another reason to long for a G90.

=Brian

[ecrabb]

[overclkr]