Paul L said:

Just for curiosity, I used a standard RCA video cable and plugged it
into the digial coaxial jacks of my DVD player and Yamaha reciever. I
get very good audio from the connection. Is digital coaxial just another
fancy name for RCA? Does using a more expensive digital audio coaxial
cable really improve the sound over and RCA cable?

If you can't hear the difference, don't pay the extra money for the more
expensive version. (That was originally in a fortune cookie, but it's
relevant here.)