Somewhat louder than "normal" plasma buzzing seems to be common, and there are certainly many complaints of it being "excessive" or "very irritating". Unfortunately, there is no answer to your question. The noise varies from panel to panel, presumably due to loose manufacturing tolerances (these are glass, so each panel will be slightly different). PLUS, I've found that some people can't even hear it because it tends to be high frequency. The few instances of Samsung correcting the buzz were the result of a complete panel replacement (however, this very same repair has also gotten some people a panel with MORE buzz). I have had a service tech look at my panel and it does not appear to be an easy thing to convince them to perform this repair:
He first told me the buzz was normal.
My response was that my friend has the SAME TV with ZERO buzz.
Then he said I probably have bad power or grounding problems.
My response was that couldn't be possible, the wiring was recently updated and completely to code. I asked to him use an outlet checker to verify proper wiring. He checked and had no response.
After all that, he went back to insisting the buzz was normal. He had no instrument to measure the level of buzz.
I know I can keep escalating it with Samsung, but after going through one repair (new main board for different problem) I have absolutely no intention of allowing them to gut my TV again. They will keep replacing things until your warranty runs out or you get fed up, they will not deliver you a brand new TV. In doing so, in my case, they have already wiped out the factory calibrations (service menu settings) that give the TV a great picture right out of the box, and they have not been able to fix it. It's just not worth ending up with new problems after these repairs. I'm not saying Samsung won't make it right eventually, but it's not an easy process.
Moral of the story:
Just make sure you have a good return policy and don't spend too much time on the install. Get it up and running, then decide if it's a buzzer and maybe try an exchange if necessary. It's luck of the draw, plain and simple.