To add to Gs5556 comment - the further apart your speakers, in general, the larger the soundstage. Try STARTING at 7 feet and opening this distance up to at least 9 feet, until the center image loses focus.
What determines speaker distance?
What determines the spacing between the speakers? I've seen a 1.3 formula for setting the distance between each. If I have a 9 foot distance from the speakers to the listening chair that would make the spacing approx 7 feet? Seems a little wide to get a good soundstage. Are there are any other "general" guidelines for getting a basic spacing between the two?