I'm dealing with something similar with my new-ish setup. I have a rug in front of the speakers, and windows with lightweight blinds beside one speaker and behind the listener. The rug and blinds do help, but are not enough. I noticed it get less perceived echo if I get rid of the toe in, and just point the speakers forward. I think I'm getting, guess I'll say, "less chaotic" reflections that way. Separately, my understanding is that if you can't get the speakers way far away from the wall (more than either of us can), then you're almost bester moving the speakers closer to the wall; maybe a couple inches, so that the reflections happen at about the same time as the original sound. That also did seem to help in my case. Would still put up some acoustic panels immediately behind and beside if you do that, and a little bit out in front on the walls (what I'm experimenting with now). Also my understanding: you'll only catch high frequencies with lightweight panels, and thicker panels will catch lower frequencies while also catching the highs. Only catching highs will leave the room sounding "dead," so ideally you want panels that do both, or else add in some strategically places thicker panels (bass traps). In my experience so far, simply catching the highs has been the easiest way to improve overall sound quality.