CurtPalme.com Home Theater Forum

[jcwhite57]

G90 with moome IFB-HD V2 card.
Hurley high gain screen

I performed a search for "G90 uniformity" and over 1200 hits were returned. At least the first two pages had nothing to do with uniformity. Anyway:

Problem:
My screen is a high gain Hurly and has the usual problems associated with that screen type. Namely hot spotting and color shift. I like the screen very much but it could be better. I attempted to adjust brightness & color uniformity. The projector goes into the adjustment mode for these functions and am able to change the settings but the screen changes are very subtle to say the least. My Barco 808 had a contrast modulation board installed and the effects were very obvious. Had a unity gain screen at the time so didn't have much use for those functions.

Question:
Is my projector working correctly or do I have a hardware problem?

[CIR Engineering]

Your projector is working fine. The uniformity controles are really only going to work on a 1.3 gain screen or less.

Even with a true contrast modulation like in the Barco you will have a mess unless you are only wanting to optimize for ONE seating position.

craigr

[jcwhite57]

Thanks Craig. So the effect woulld be more evident on a lower gain screen. But lower gains screens don't really have those issues. Too bad, it would be nice to compensate for my screens deficencies. The image quality on the Hurely is very good except when it contains a lot of white. I played with contrast modulation when I had the Barco and didn't like it. The image seemed to have a haze covering it so I turned it off.

[CIR Engineering]

Contrast modulation is riddled with problems...

The G90 uniformity adjustment is there to help balance out the non-uniformity that exists naturally on all CRTs. A CRT is always brighter in the center and dimmer towards the sides. The G90 contrast modulation can fix that on a low gain screen without too much delirious effects.

craigr