Please comment on your experience with Plantation shutters. Yes they look great,

but do they act as good sound diffusers over windows? Has anyone noticed they improved the sound in a room with windows? I am thinking they may do a good job when tilted, but not fully closed. Perhaps even better than 2 inch wide standard shades?
I plan on toe in for sure. My wife will not allow drapes, but she loves these expensive plantation shutters. No magic sound properties it seems! 
In my limited expertise, I think the bandwidth over which shutters diffuse is going to be fairly narrow.
Install drapes that hang outside of/over the shutters.
Keep the drapes open except when you want to listen.
Tell your wife it is a necessary energy saving measure for the cold Minnesota winters.
Good luck with that.