Would diffusion help in this space

I would put 2 fake ficus trees side by side right in front of the TV. Move them to the side when you want to watch.

Musicfile,

If you put a cotton blanket over your tv, you will have a certain sound. A wool blanket will give you another. Different materials absorb and reflect different frequencies. People roll tubes for a different flavor, I suppose you could roll blankets. (I'm half serious here).

Ficus trees have alot of tiny leaves that I think would help the center fill your speakers are trying to do.

As a side benefit, you could impress people with the quality of your tv picture. Just say "Look how real those trees look". :-)

Rsjm80, I do love skeptics. I keep them in a skeptic tank.

Musicfile,

The fake ficus is light and easy to move. I bet you could move them as fast as taking the blanket on and off.

Let your wife pick them out, they don't have to be that big. I bet she will like them more than the blanket.

Have fun.