Front call absorption, pls explain theory...

The front wall reflects sound waves, either from the speakers themselves (not so much if you have front firing boxes, lots if you have bi-polar) or bouncing around the room, first reflections principally off the back wall. Deadening the wall behind the speakers allows you to hear the direct signal from the speaker more clearly, without pollution from these reflections.

With front firing boxes you can achieve almost the same effect by deadening the wall behind the listener as this will kill not only the first reflections from the speakers but also deaden second reflections off the side walls.

Personally I find the sidewall reflections most objectionable and focus on reducing them. They do the most damage I think. Most of the benefits from deadening the wall behind the speakers can be obtained by just pulling your speakers out into the room about 5ft. Putting diffusing (not deadening) stuff on the wall behind the listener can also be very effective in quieting reflections.

FWIW, I, and I think many others, prefer the effect of diffusion more than deadening. Some reflections are a good thing. In real life they contribute to the spaciousness we enjoy. A lot of recorded music can be on the dead side and benefit from these reflections.

Tboooe, You can successfully deal with sidewall reflections by using a severe degree of toe in, i.e. setting the axis of the speakers to cross in front of your listening chair. If you do that, you can also increase the space between the speakers and your listening position, if room size allows. Something to play with on a rainy day. :-)