digital tv sound quality

[johnny37]

I recently bought a Toshiba digital tv and the sound quality was so bad with lots of irritating backround interference the online retailer replaced it. It sounded like a dodgy speaker. I used a freeview box before with no apparent problem. The replacement still has a sound problem though not as bad as the first one. My question is this. Could the problem be due to a poor signal which was not apparent with the cheap freeview box but has now been highlighted by the better quality technology in the digital tv? There is no problem with the picture, only the sound.