If your company enjoys having an open floor plan, then just do it. When in doubt, value happiness over anything else. We have music playing constantly at the office with everyone sitting on long community tables. It's a relaxed, fun atmosphere, and I enjoy doing work there.
When you want to go into The Zone, we have closed off offices that you can do that in (or, alternatively, just stay at home or go to a coffee shop and get your work done there).
Efficiency in workers isn't the end-all game. There are a lot of metrics beyond just "what is the most work we can squeeze out of our employees today".