You have already wasted a lot of effort and time by replacing your AVR and DVR. This is not a new problem and there are several threads abut this problem. It has to do with the Directv HD DVR and the feed it's receiving. This problem has also happened with other cable satellite companies and DVR brands. Google Directv HD DVR audio drop out and you will find many reports and information. This problem might get better or worse for you depending on where you live and the feed coming to you.