As it is now I have almost absorption on a lot of places in my room except the rear wall. It is naked. Only corners treated.
I really like how diffusers look like So I ve been thinking about building a big rear wall consisting of skyline diffusers. Probably absorption will be the best bet, but I feel my room is already starting to sound dead (small space 3,65x3,5x2,8).
I've already made some calculations with the qrdude to take into account the minimum distance from listening position to the rear wall.
What do you think?
One more thing;
I have 3 long bookshelves that are hanged on the front wall on my room, and I cannot move them without damaging the wall. Before I had some cardboard boxes filled with insulation, and the boxes sitting on the shelves but I decided to remove them and build proper panels (to put them on ceiling/wall corners) with that fiberglass.
My question: is it bad if I fill the shelves with a mass (ex. books) to act them as "bass trap/broadband absorbers", even if the absorption is going to be bad or uneven? Would you leave them empty?
Your room is pretty small and close to square. The largest problem you are going to have it low end decay times so I would recommend THICK absorption on the back wall. If you want to retain some of the upper frequencies then put slates over the absorption to help scatter/retain some upper energy.
More about low end in rooms. Bass Traps and Understanding Low Frequencies - GIK Acoustics