Creating a Large Sound Stage

Don't forget that speaker placement also has a lot to do with good sound stage.

Just about every audio related variable you can name will come into play here.

It would help greatly if you add photos of your room and list equipment in a Audiogon Virtual System. 

lack of strong direct reflections, diffusion between them, excellent bass. 

Diffusion to the sides is also usually a good idea. It's preferred to pure absorbers in some cases, especially for imaging. 

lack of strong direct reflections, diffusion between the speakers, excellent bass. 

Diffusion to the sides is also usually a good idea. It’s preferred to pure absorbers in some cases, especially for imaging.  Absorption on the floor and ceiling are often missed but very important. 

lastly, proper toe-in.  this is often less than people use.  That is, audiophiles will tape a cat LED pointer to their speakers to point them straight at their heads when many speakers are designed to play straight into the room.