I've got a small set of monitors and a sub in a small square room. Far from an ideal situation is being kind as the room is awful. The system had no slam or whump in it and had a somewhat congested quality overall.That changed by moving the listening position closer to the speakers. The chair went from a semi near field listening position to a very near field spot. It was probably a 4 or 6 foot change in the position of the chair.
The system has slam in the new listening position and has lost the muddied congested quality.