If it's new I'd swap it but keep in mind that most sets have barely acceptable speakers. Most of us think it's to do with keeping the cost in check since folk that care about sound get a receiver or if they just want a little better a speaker bar.
I've just got a Samsung LE32D403
Software Version; 2012/08/17-001010
Nice enough TV for the price but it has issues with the speakers vibrating.
This mostly happens if I want to watch a film/movie and set the sound settings to Movie!
It still happens even set to Music or Standard but to a lesser extent in that order!
E.g. Watching the news, the voice of the news reader sometimes sets the speakers vibrating at the lower frequency parts when someone is speaking or music is playing!
Had to change sound setting from Movie to Music when watching the 2009 Startrek film as the vibration was very bad
I've seen a few posts on the web that others have sound problems with this TV!
I've checked all screws on the back are tight etc!
What can I do to fix this?
Thanx for any help or advice.