Interesting, I noticed when I had absorption on the front wall it sucked out the highs, on the back wall behind the MLP is totally different. I started with the side walls and after the third panel it sounded dead. That is when I found a good resource and changed it up, interleafing absorption with diffusion, Now it is the way I like. Totally get it though, dead rooms are painful to listen in.
The problem with absorption panels- it kills the fine details
If you’ve ever removed your absorption panels, you’ll find that you’ll hear a lot more detail and there is more openness. Truth is all those fine pressure amplitudes that add so much to enjoyable listening are considerably extinguished with absorption panels. The room seems quieter with absorption panels because all the fine detail is diminished.
It sounds different, so people think it sounds better. Absorption panels can kill good sounding music. I removed most of the absorption panels, and things actually sounded better. All the furniture in the room and the bookshelves were doing their thing in a great way. So I’ve concluded I really don’t need all that crap on the walls.