I don’t have much flat surface behind the speakers, I also have essentially no absorption material behind the speakers, or really even in the entire room, only the loveseat to the left, the ottoman and couch.
I know people have recommended removing the monitor, but this is a multi-purpose room, watching videos is the bigger usage of this system, than Music only. Though I try to optimize for music.
I’ve thought about heavy drapes in front of the built-in cabinets and fireplace. I just haven’t been inspired enough to buy and install them.
Attached is a picture about a year old, changed DAC, though speaker and monitor are effectively the same.