Super Bowl sound problems?

Did anybody else's volume take a nosedive in the first half of the Super Bowl? Ours did. I'm not an expert, but it's definitely the NBC signal as far as we're getting it, because the volumes of the other stations, network and cable, are all at normal albeit negligibly different levels.

I couldn't find a single posting about this in a cursory Web search, but I did find postings on similar volume nosedives from years past for Super Bowls on other networks.

Is there an expert who can explain what the deal is?

Seems pretty egregious for major networks to fubar audio on such a major event.