Paul L wrote:

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?

No.

Unless you're into audio voodoo ! In which case all bets are off.

Graham