Techs at Fios told me repeatedly that HD sound due to bandwidth or something will always be lower...My problem on 5 sd channels is the sound is BOOMING and DISTORTED enough so that oit sounds like my 60's will explode! I of course never watch the locals in sd but last night the wife switched to 4 instead of 504 and ...oh my god!...I wonder if a tv regulator would work, but that has rca connections, don't see how I'd get 5.1...