You have RGB limited, RGB full, and Y Pb/Cb Pr
For the cable box the correct setting should be Y Pb/Cb Pr
/Cr since this is how your cable box should be outputting the signal.
For PC it should be RGB full.
The output from pc is different than for cable box. The PC outputs video 0-255 while a cable box will use 16-235 (well, actually it's Y Pb/Cb Pr
/Cr). 0-255 is rgb full in playstation settings, 16-235 is rgb limited.
What these numbers indicate is black and white level. 0 is the blackest black for rgb, 16 is the blackest black for limited. Since the ranges are different, if you use the wrong settings you will either get a washed out picture, or a picture that looks too contrasty (mostly notice black crush and loss of shadow detail).
Auto setting on projectors should recognize the signal and switch automatically...but on mine and probably other projectors this doesn't work right all the time. It only auto switches from YUV (Y Pb/Cb Pr
/Cr) and full RGB but it doesn't distinguish between limited and full RGB which makes sense but is annoying.
I think it's generally best to set everything to Y Pb/Cb Pr
/Cr. Mainly because this is what the cable box outputs and most of the time the cable box is the least flexible source. In this case the projector would be set to receive this signal and the ps3, cable box and computer should be set to output this signal. Some PC setups (like mine) can't do this and if I setup my pc to output RGB limited, I will have to switch it over to RGB full whenever I use the pc on the projector. The way I have it setup is that the ps3 and pc use rgb full. So if either are sending a signal to the projector the projector switches to RGB full, when it detects a signal from the cable box it switches to YUV. I also have a plasma tv connected to the same system and that does give me issues since I have to go to expert settings and change black level from low to high depending on whether i'm using 0-255 values or 16-235 values. I just have to do that manually and live with it. If I could get the pc to output Y Pb/Cb Pr
/Cr, then I would setup everything that way and be done with it.
Based on your posts I think that the RGB setting for that projector is ONLY for 0-255 levels, you don't have a setting for RGB 16-235. So anything using RGB limited would look screwy as the projector thinks the colorspace is 0-255 when the source is outputting 16-235 (image is washed out).
The way you currently have things setup: your ps3 should also be set for rgb full. And if you want to use the cable box you'll have to set it to Y Pc/Cb Pr
/Cr. Perhaps try the auto setting again to see if it works like it is supposed to.
Yes it is a headache...to answer your wife's question....Avsforum. That is how we learn all this crap. (now try all this with 2 monitors connected to the same receiver which require different settings...Fun Fun Fun)