It sounds like you may be sitting too close. Try moving back if your room permits. You could also try varying the tilt of the speakers front to back to get the gap you desire,
"In the manual, Duos require a set-up whereby "
I think the key word in that sentence is require, which I would view as a suggestion rather than a requirement. It may be true that they achieved what they considered to be the best results with that set-up, but I would suggest that your room and equipment might require a different configuration.
That said, it is true that optimum performance requires optimum placement and that may well be different than what the manual says. Unfortunately that can only be determined by experimintation.
"In the manual, Duos require a set-up whereby "
I think the key word in that sentence is require, which I would view as a suggestion rather than a requirement. It may be true that they achieved what they considered to be the best results with that set-up, but I would suggest that your room and equipment might require a different configuration.
That said, it is true that optimum performance requires optimum placement and that may well be different than what the manual says. Unfortunately that can only be determined by experimintation.