I'm tried of some people saying, dismissively, "all plasmas buzz"- I'm sure they all resonate at some level, but it's pretty short-sighted to ignore the fact that there is likely to be different varying degrees of buzz.
There are some older plasma models that buzzed, but had "fixes" that included opening up the chassis and tightening down any loose screws, etc. While I'm not suggesting that anyone do that, we need to think about what the buzz actually is. It could just as easily be that while the panel itself is resonating, the *noise* that people are hearing is coming from some part of the chassis (or the entire chassis itself) resonating as well. This could explain why some people notice that the buzz is reduced when the panel is mounted on a wall: with all 4 mount points engaged (vs just a stand at the bottom), you're giving the kinetic energy someplace else to go, essentially dampening the vibration.
Anyway, I don't even own a plasma ATM, so these are all speculations on my part.
Meters: X-rite i1 Pro 2, X-rite i1 Display Pro
Software: Spectracal Calman DIY, ControlCAL