In acoustical terms 99% of our rooms are small - 30x20x12 or 15x13x8 both are small acoustically speaking. However those two room sizes will require different approaches. Small room acoustics are very challenging.
The challenge is to get the most out of your space and spkr placement / listening position and addressing room acoustics are the single biggest influence on a system, more than any piece or gear IMHO. I’m not into HT, only 2-chnl, but generally speaking many of the same principles apply
- Addressing bass is prob first priority along with first reflections. Putting pillows and or thin 2-4" panels in corners will do nothing to the lower bass region.
- Using only absorption (a lot of it) wont give you a balanced / linear response, so a balance of absorption and diffusion is needed.
- Unless you are building a room from scratch and designing true corner trapping via a acoustician, floor to ceiling bass traps in corners (tube traps, tri-traps etc) are a good starting point.
- 4-6" broadband at first reflections AND ceiling. Treating the ceiling is very overlooked. Its actually "free" real-estate
- Diffusion > this is tricky as this can be applied to various areas, but can also create a lot of problems if not done correctly. I would get advice on how to implement this, but on ceiling and front wall are good spots. The back wall (behind you) is also good, but req minimum distances to listening position
- Multi subs give tremendous value and impact for the bass/sub bass region.
These are just some basic ideas, but get a mic and REW and measure your room is where I’d start. Also, I think its a matter of priorities as well. If you are fine with "whatever" and it sounds fine, that’s cool. If you want the very most from your system and are willing to put in the time, you must deal with spkr positioning and room acoustics, no way around it.
DSP and the like are also no substitution / fix. Get the above right first, then if one wants to dabble with DSP, that comes last IMHO.