CurtPalme.com Home Theater Forum

didaschi · Joined: 27 Jan 2009 Posts: 44

Hi,

for some days I try to calibrate my Sony G70 with hcfr software and sensor.

Luminance shows clipping and I have no idea how to manage it.

First picture is using RGB Connection via DVI to 5xRGB Spatz box.
Second shows luminance with MoomeCard and Clipping

Moomecard gamma is on max. and contrast on middle position.

Sony G70 contrast is 60 and bright is 55.
Gain and Bias is 127 of 255 for green

Please help.

didaschi

CIR Engineering · Posted: Mon May 07, 2012 1:42 pm Post subject:

Why did you change the contrast setting? This needs to be set with an oscilloscope connected to the green pin on the multi pin connector. Feed the HDMI card a 100 IRE white window. Then adjust the contrast pot until you see exactly 0.7 volts peak-peak.

The contrast pot being set wrong is the most likely reason you are seeing clipping. You are probably sending to high a voltage for RGB from the card and the projector can not take this.

The other possibility is that your gamma is set much too low on the card.

craigr

didaschi · Joined: 27 Jan 2009 Posts: 44

Hi,

what do you mean with you see exactly 0.7 volts peak-peak?

Do I need an oscilloscope to see it or is there anything to see on the 100% IRE white windows?

Regards

didaschi

CIR Engineering · Posted: Mon May 07, 2012 4:55 pm Post subject:

You need an oscope to see it.

A less precise way, but not too bad is to do the following.

Put a test pattern on the screen that shows whiter-than-white in 1 IRE graduations. Adjust the contrast pot on the board so that you can see all of the white levels through 255. Once you can see all the white levels turn the pot a little more so that you have some overhead. Don't go too far or you will compress your gamma because the peak-peak voltage may go below 0.7 volts. Just get to where you can see all the whiter-than-white bands and then give it a little bet of extra turn (maybe 1/4 to 1/2 turn).

craigr

didaschi · Joined: 27 Jan 2009 Posts: 44

Hi,

thank you for your help. I will try it.

didaschi

Gannon · Posted: Wed Jun 06, 2012 11:32 pm Post subject:

I don't know if that is the solution.

I have the same card in a G90, and both my Quantum Data signal generator and the client's Sony Playstation not only clip like hell...it totally freaks out the grayscale. Turns the middle seriously green, which cannot be corrected by anything.

I made the mistake of adjusting the damn contrast-control-that-isn't before reading this thread.

BUT the problem existed prior to that.

I set levels with another BluRay player...a multi-region Sharp...before trying to get the game right. So I should be able to return to the correct previous setting without trying to find an oscilloscope 1,300 miles from home.

(for the record, I've had tonnage of issues trying to kluge the Playstation into high-end systems...which Sony refuses to deal with)

This card was installed by another firm, along with a cheap HDMI to RGBHV convertor set...which caused the client's system to not work for two years. (there were extraordinary issues with some tragedy and insurance delays) They might've tweaked the gamma on the card beyond reasonable.

So...why does the Sharp BluRay play perfectly...but BOTH the Quantum Data and Playstation clip it to sh*t?!

This is not my first time having issues with a finicky Moome setup...but I never, ever got any form of reply on the previous one.

I hope to hear from Moome directly on this one...so we can learn a procedure for setting these pots. If they should not be touched, they should NOT show for anyone to fiddle with. Period. A simple drop of nail polish on each would set their adjustments in the factory.

Anyone?! Bueller?!

Cheers,
John
Detroit

(temporarily north of Boulder)