Didjdude

Double-check feedback on the make/model of your new satellite receiver on Video forums. (AVS is a good one) If it is a HD capable receiver, some of these have audio dropout issues. I returned a Sony HD200 that I was having reboot/freeze occurrences. I did not have the audio dropouts with my box but a high percent of 200 owners did experience heavy audio dropouts.
The Zenith version had the same issues with dropouts as did the Samsung competitor at one point although the Samsung STB (may) have sorted out on that issue (I have not checked status on these recently. I am not as familiar with these audio dropouts recorded on the non-HD satellite receivers currently at market but know that some have had dropouts reported.

It may not apply to your model, but it is a common enough complaint with various STB’s at the moment, that I would recommend you ruling this out, - since you mention your dropouts began with the addition of a new Direct receiver to your system.