RynMan wrote:So the conventional RCA cables don't support 5.1 surround?
Correct
Standard RCA Cables only transmit two channels of sound, Right Stereo (Red) and Left Stereo (White or sometimes Black). The only way in order to get true surround sound is by using HDMI, optical, or digital coax cables since they transmit digitally. It is also possible to get surround from RCA, but only if your surround amplifier can manufacture 5+ channel sound from two channel sources - like I described above with Logitech's Matrix Mode, etc.