First, make sure u are using stereo and not any surround stuff (I assume you are using only two front speakers). Judging by your DVD viewing, I guess the only problem u got is during the d* tuner mode so I suggest u call the dealer or make a return trip asap.
I own an onkyo and I know these tips are a no-brainer but still makes a lot of sense to me. I feel for you, I still listen to my radio.