Does the same thing happen if you use a different HDMI port in the back of the TV? Also, you might want to call DirecTV and have them reset/update your box. In most cases, they can do it remotely.
Keep me posted.
I purchased a 50 inch Samsung Plasma about 3 weeks ago (model PN50A650) and have noticed intermittent sound drops while watching TV broadcasts. Have not watched a DVD as of yet, so unsure if this will also be affected. I would say it happens fairly frequently...at least 10 occurrences in a 2-3 hour span. I have the TV connected to a DirecTV HD box via HDMI and also have a Sony soundbar connected with HDMI. Anyone else having similar issues? Any help/suggestions would be appreciated. Thanks.