I just purchased a new Onkyo HT-R510 receiver. It replaced my trusty Yamaha RV902. I also hooked up a Samsung DVD player with component cables and used a Toslink for my audio connection to the Onkyo. The audio blew me away. It was outstanding in comparison to the Yamaha, which was a 5.1 ready receiver into which I had connected the 5 composite connections from my Toshiba DVD which had an onboard DD decoder. I did some minor adjustments but for the msot part, left the Onkyo default settings stay. After watching the Hulk tonight though, I noticed the Onkyo was extremely hot on top. I have my Comcast Digital cable converter box sitting directly on top. OK....long enough buildup here....my questions: 1.Is the heat buildup normal for a long movie(volume set at about 36)? 2. Should I remove the cable converter box and rearrange so the new Onkyo is completely open on the top side? 3.How come my Yamaha 5.1 ready receiver and Toshiba DVD player combo did not sound nearly as good as the Onkyo and Samsung DVD combo?