My friend just picked up the Sony DVP-NS755V SACD/DVD player. The guy at Best Buy told him he needed the 5.1 cable to listen to SACD's. My friend already has a coax cable, but the Best Buy guy said it wouldn't work for SACDs. Is this true (that he needs the 5.1 cable rather than the coax) to play SACDs? It sounds to me like the guy was just pushing a cable that my friend didn't need.