Solution for 4 foot width hall to sitting room

I have a hallway that goes into sitting room but don't want to put a door and the frame into it. It's purely for stopping noise from outside coming all the way into the sitting room (and vica versa). Anyone know whether you can get a split or folding door this size as I'd like to open it for a lot of the time as well. Something along french doors is what I'm thinking.Curtains is not my thing either.

4 Feet will likely be too narrow for an off-the-shelf solution, but a good carpenter/ cabinet maker should be able to custom make a pair of doors that would recess into the walls and be quite inconspicuous when open.