I watch OTA broadcasts and run Optical Audio out from a Vizio TV to a Sony Soundbar AV system. I have 2 options for TV audio out to select from - 1) "Auto" which reads as Dolby Digital 5.1 on the Sony AV, and 2) "Force PCM" which reads as PCM 2.0 on the Sony. The PCM option sounds better (or louder really). My questions - Which of these 2 TV audio our options do you recommend I select? On a soundbar AV system that tries to mimic surround sound, which is better - DD 5.1 or PCM 2.0?