help thiel 2.4 placement???

i am having some problems placing in my room a pair of thiel 2.4, acording to thiel they should be far away from the walls, they recomend 3 ft at least from the back walls and 5 ft from the side walls.
i did this and i am not getting any bass, if i put them closer (1 ft) from the back wall i get much better bass but thiel does not recomend this.
right now i have them 2.5 ft from the back wall, 6 ft apart from each other, and the listening position is 8 ft away. sound is ok but i know it should be better.
does any body have experience placing thiels, please help
thanks in advance.