If that's a real brick wall, not a metaphor, in your listening room, you are lucky, especially if it's behind your speakers. The rough, jointed surface ought to diffuse the highs very well. You can try other treatments on it, why not, but my guess is that other things, like side reflection points, would need more attention.
Jim Smith's book Get Better Sound is an excellent reference for matching your system to a room. His techniques really work, they have made my system sound fantastically better.
http://www.getbettersound.com/
Jim Smith's book Get Better Sound is an excellent reference for matching your system to a room. His techniques really work, they have made my system sound fantastically better.
http://www.getbettersound.com/