I'm wondering if it could be related to the compression on the channel? I know I get raspy sound occasionally (news and other "lo-fi" channels seem to be worst) from the digital transmission of overly compressed channels.
I own the 42" model of your TV and the TV sound is actually really good - warm and clear.
I'm getting ready to return my Samsung HL-S5687W due to poor, raspy sound. Over-the-air sound on HD channels is poor, and audio from standard Direct TV is terrible (it takes a month in my area to get HD satellite installed). It sounds good when run through a receiver, but I'm not going to run a 1000 watt amp all day to watch the stock report.
I'm considering a Sony KDS-A2000. I've checked and rechecked, and the reviews omit this information (on all HDTV's). Any suggestions on a HDTV which can stand on it's own sound-wise?