Bart . I'm of the opinion that the room is one of the most important components..it's what mangles the sound before it hits your ears. Money and time spent on treating it is well spent.
My room is entirely clad with a special acoustic panel that is slotted and pierced .. all on battens with rockwool between the panel and the wall..a small airgap
The panels do a little diffusion and absorbtion the ceiling has the same in the void , but for diffusion I use a faux Rockwall .. not the ideal diffusers but they work
in every corner I have both tube and flat bass traps .. tube deep into corner and flat traps straddling them.. behind my listening chair I have 2 absorbtion panels
Carpets on floors , floors are that fake wood , but have acoustic underlay
All windows barring 1 were replaced with glass bricks
Dedicated pure sine wave inverter , 5kw , fed by solar charged batteries supply ultra clean power (here in SA , brownouts and surges is common
No isolation or any serious tweaks .. my system sits on a coffee table as the rack
My listening chair is an ergonomic office chair from ergohuman , the Nefil .. tried about 7 listening chairs before I got the ideal one
The double doors to my room are soundproof .. the room is as well .. I can play as loud as I like..my bass has actually cracked the ceiling
Here are some pics of the room etc .. some items have shuffled around as the pics werent all taken at the same time .
My stack
My Rack