Dynaudio's website has some information on speaker setup. It involves the 1/5 concept. The center axis of the front plane of the speaker should be 1/5 the distance off the back wall of the depth of the room and 1/5 the distance off the side walls of the width of the room. If there is a wall behind your listening position, then that position should also be 1/5 the distance off the wall for the depth of the room. This concept should get you out of any standing waves and put you in the ball park of the sweet spot. Of course you still have to listen and adjust to make it sound best for YOU.
Happy Listening
Happy Listening