Could you please speak up?

Argh! I've found the one weakness of shared workspaces. When I'd like to focus on something, the guy behind me is on the phone with the customer trying to figure out the requirements and then he's explaining them to the QA guy. His voice is naturally loud. He could use so much less volume and still communicate. 

He isn't doing anything wrong, I'm just having a bad day. I really hate it when I don't like what other people do for no reason other than I'd like to have silence.