This is certainly one of the small issues that is so well-known, people have stopped talking about it long time ago. Specifically –  in one of our conference rooms we have an old Polycom phone. It is not too bad – as far as very old phones go – but even in the small room, everyone’s default voice level is raised to the level of shouting. That is terrible. Sure, you think you are just making yourself heard, but it is impossible not feel stressed and tired, on both sides of the phone, after screaming and being screamed at for an hour or two. As the meeting goes on - antagonism builds up driven purely by the emotion of screaming at your teammates.
Think about it – does your company expect you to SCREAM at colleagues working TOGETHER? Of course not – they just do not realize that we are hardwired to remember emotions and fall into patterns without remembering the reason you fell into the pattern in the first place. (my interpretation of pp. 276-278 of ‘Upside of Irrationality‘ by @danariely)
So office managers, and other managers, when you invest in cherry furniture, just leave a little money to buy some decent audio and video equipment – it will pay off very very quickly for your team.