We've had issues in our office where a new employee (actually a co-op was completely incapable of controlling the volume of their voice. People on the entire other side of the office, with earbuds on under their over-the-ear headphones, were having a hard time working. That person ended up leaving, and I ended up sending some frustrated IMs to other people on his team. Eventually, I just moved my desk and the co-op learned to keep his voice down, but for that length of time it was impossible to concentrate for more than ten minutes at a stretch.
