When you say you lose sound what exactly happens? Does it drop out momentarily or completely stop?
The cable will not affect the color on the TV if you're using HDMI. A good place to start is put the TV in standard mode (not dynamic). Next, get a calibration disc like AVIA or DVE. They are much more extensive than the THX Optimizer. If your Samsung has an "Edge Enhancement" option in the video settings I would also recommend turning that off. Also remember that when you change video modes (Dynamic, Standard) on one input it doesn't affect the others so you have to do them separately.