Great explanation of the asymmetry issue. I had assumed the only issue would be with the first reflections of the mid-high frequencies and that they could be dealt with by absorbing them. I didn't realize there would be the bass-gain issue. I suppose some thick bass absorption would help. I have considered a floor to ceiling wall as a divider, maybe coming out 2 or 3 feet. Would that be enough to balance the bass? Or would the newly added reflections be an issue?
From that one previous picture, I can't tell exactly how much of a permanent install your place is. Okay, let me first address some issues, then I'll come back to my suggestion.
Yes, there will be a gain in the bass and mids. Even if you fully treat the right wall, it still won't fully address the fact that the left wall is still so far away. Acoustic treatment can fix some things, but you'll still need room correction. The problem with most of the room correction is that it only works for the one location. You'll have to jump to something like Trinnov for serious gains. Even then, room correction is really only meant to deal with an already good room. In poor rooms, even moving a few inches will ruin the sound.
If there were other pictures of the room ensuring 360 degree coverage and location of windows/doors, that would really help.
Bottomline:
The bad - currently, the positioning of the speakers is really atrocious. I won't sugarcoat it. Since the room is squarish 20 x 20, that does introduce bass problems, but it's not something I'd worry too much. It can later be addressed with room treatment.
The GOOD - Your room is 20 x 20!!! That's a great size and gives your rig a LOT of potential. The room is the most important thing. Sure you'll have to treat both a small and big room, but there are limitations in small rooms that one has to live with. The fact that your room is 20 x 20 should make you happy and give you serious hope. The biggest battle has been won!
Recommendation:
1) More pictures to really assess this situation.
I'm not sure how flexible the electrical and video setup is in the room, but hopefully it can work.
To give you hope, I previously also didn't have my room setup correctly for audio and video. The rest of the family didn't care about it. Then one day I decided to do it right. I made a sketch of dimensions and all applicable lengths that were important in the equation. I have it currently down to +/- 1mm. Next was assessing which features of the room, such as speaker location and listening location, were fixed and to be dictated by physics rather than convenience. These things were fixed and locked. After that, I imagined about how to relocate the other furniture.
Took about 2-3 hours of just assessing the room, the ports, furniture and see how I would tackle it. The actual moving part and rewiring everything took 2 full days. LOL my family was thinking I was just wasting my time moving everything around. I went at my pace and stuck with it. The pre-planning really helped.
Got everything wired at the end of second day. They actually ended up liking the symmetry and what I had done with the furniture. The real moment came in when I got the family on the couch and pressed play. Within 10 seconds, their jaws dropped. The 2 day journey paid off. Even they could tell right away that it sounded much cleaner and that the bass sounder clearer and "thumped better."
Based on your equipment and your passion for audio, I think it's a no-brainer for you to seriously consider getting the symmetry right. Having the symmetry right will make so many things right off the bat. Then when you add equal treatment, you'll again experience natural sounding improvements. If after that you still want to add that last bit of room correction, you'll get more out of the process.
I've spoken to some high-end designers and they have told me that many people sometimes get too consumed about thinking of sound in terms of frequency and phase, etc. It should never be forgotten that sound is acoustical ENERGY and pressure in a system. When you start imaging the sound in terms of energy and energy radiation, the symmetry aspect makes so much sense. Right now, you have that right speaker in the corner where all that energy is a mess.
You really owe it to yourself to hear both the speaker and the room correctly. As I already said, you have the right equipment and a good room. Now it comes down to planning and hard work. It should hopefully involve no money, just some time. The reward will be huge.
