I am pretty new to this and have a quick question. I realize you need an digital cable or an optical cable to create full surround from my DVD player to the reciever. My question is if when I plug in either one of these cables how do I set my reciever to get full suround sound. I have an older SONY 5.1 reciever and it does not have an button to use either one of these sources. Or will the reciever automatically go into full surround sound once connected?