To expand on this a little further. If you use the digital output from your DVD palyer (either optical or coax) your receiver will be performing the digital to analog conversion, vs. sending the signal using the RCA connectors. In this case your DVD player will be doing the conversion. All DAQ's are not created equal, so one may sound better than the other by virtue of the difference in the DAQ's, not the difference in the cable type, although the latter will have some effect as well.