While playing music on headphones can help block out conversations, it is still a distraction. It's just not as annoying as hearing other people talk.
I've worked in places where it was an issue. And it's a very difficult one to address. "Please be quieter" is much more socially acceptable than "Please use deodorant".
1. In private, tell the person "I don't think your deodorant is working well enough. Just thought you ought to know."
2. Go to their manager, and have the manager say pretty much the same thing, not mentioning that anyone but the manager noticed anything.
Almost anything else comes off as boorish.
An open room needs plenty of space.