You can call it an open office that amplifies communication in the team, so noone will notice that they're almost piling up vertically. And the problem is not just noise. Too many people breathing the same air leads to rising carbon dioxide levels which makes concentrating quite hard. Unless the office was literally built for large crowds, the ventilation will usually be insufficient to cool the office in summer and to provide adequate levels of air flow.
I stopped calling those things "open offices" and use the term "laying battery" instead.