I'm new to this, so hopefully somebody experienced can give some insight. I'm not gonna list the models I have cause it's not important. I recently got my new 65" smart tv, so naturally I had to set up my cheap RCA 5.1 system with it. First day it's hooked up, my optical input quits working, so now I'm using av cables which makes the Dolby digital setting not work. I'm pretty content with the sound, but it's not very loud. I have an old Kenwood 5 channel receiver which puts out more power and looks like it has better specs but needs a powered subwoofer. Should I use this receiver and just buy a powered subwoofer or go buy a new receiver that has HDMI inputs? Does using HDMI create a major sound quality improvement? Both my receivers are old so I have to use av cables. My budget is about $200.