This might help:
Get them 10" or so off the floor, and away from the wall behind them by about 30" and adjust from there. I liked mine with a subwoofer crossed over below 50 Hz and playing very very low volume. If you get rattles, check the screws on the drivers (they loosen up over time) and if the metal mesh on the back creates noise, you can run a thin foam weather strip from Home Depot around the edge of the bass cabinet to dampen the mesh.