Nasty slap echo

From those pics that room looks extremely lively. I'd suggest studying up on room acoustic treatment at one of the many sites such as Ethanwiner.com or Gikacoustics.com. Plenty of good advice. Your room seriously needs it and your equipment deserves it.
Treatments made a huge difference in my room.

Pics came though for me.
Reminds me of when I was afforded a dedicated room after our last daughter left for college. The room was totally empty when I moved in, what an echo.

Oh jeez, now I gotta go and check my comfy Scan leather swivel/recliner I've been using for years to see if it is mucking up my sound....:-)
Mapman

You say that in jest, but if the top of the chair is above your head it does affect what you hear.
A few years ago my wife bought me a very nice leather chair for my birthday. When I picked up a low-back chair at a garage sale for $5, I was afraid it would hurt my wife's feelings if I moved the expensive chair to the side. The $5 chair made a significant improvement in the sound so it stayed.