Distortions can be caused by the sound reflecting off perpendicular walls(side wall reflection). To avoid this, set up the speakers along one of the longer walls.  Position them ~12 inches from the wall behind them and symmetrical with the middle of the room. They should be the same distance from your listening position(aim for an equilateral triangle between you and the two monitors). And angled inward towards the listening position.  The tweeters should be level with your ears. If the monitors are oriented horizontally, you want the tweeters to be on the outside so that one speaker mirrors the other.