Reply To: Guidance to room treatment/speaker positioning

[Guido tum SudenKeymaster]

I won't think so. If anything it's good not having parallel walls.
But maybe you have to try (sound wise) to turn the table by 90° and then move it to the left (of course only if the sound gets better :).

If you think about first reflections…
http://webblab.sk/images/first_reflections/first_reflection.gif
(1st reflection from the ceiling is not shown but as important as from the walls)

Now, before you apply any acoustics treatments your speakers and you as the listener should sit in a position were all 1st reflection will sound hopefully the same. That will possibly not be possible in your room, but maybe you can find a space for the table with an equal distance to the left and right side and where the ceiling does not tilt from left to right.
If you turn the table the 1st reflections from the ceiling will be the same from the left and right speaker.
And if you then move a little bit to the left so that the distance to the shelves is the same and have books in the left and right shelves you already have a good 1st reflection diffusion.
You then can also move the speakers further apart so that you can build the typical equilateral triangle.