I have a SIR4040R and use the optical audio out port to connect to my home theater. On movies encoded with Dolby Digital, I get audio dropouts that increase in frequency until I do a channel swap returning to the movie but now the dropouts have stopped. Eventually, they will return during the movie and the process begins again. This happens only with Dolby Digital movies from my DVR and no other source. I have replaced the optical cable but that hasn't helped. I have 6.2 installed on the DVR. Any help would be greatly appreciated since this problem drives me crazy.