RoomFit help - Bass nulls just on left channel

[hipoagumol]

Hello,
Just purchased Dayton Audio iMM-6c usb-c calibrated mic to perform room correction.
I run with these settings and found deep nulls in the bass region response of my left channel (50 and 80 hz approx?)
- B&K
- 30-400hz
- -12/12 Gain, Q max 10
- No boost
- variable smoothing
- No multiple/moving mic measurements

My setup is wiim ultra-yamaha a-s501- Q Acoustics 3050i.
I tried without and with foam plugs in the bass reflex ports, reduxed bass energy but same nulls issue in the measured left channel response.
My room is quite symmetrical, parquet floor and plasterboard walls, so not a reflective room i would say except for cristal in doors you see in the picture..The windows you can't see on left side are shaded by Japanese panels. Picture is taken with wide angle, distance between speakers and to listen position is approx 2.5m
Any idea on what may be the reason? Is it truly so much different the left/right response or may have some flaw in my setup/hardware? Any advise?

 

[hipoagumol]

I bow to you @dominikz . Simply outstanding responses. Full of content yet concise and understandable.
I can't thank you enough for taking so much time, even built a model of my room! And being so pedagogical and kind. Truly appreciate .
I am quite new in this forum and only couple of years into audio as "enthusiast". I am engineer and obviously prefer the fact, measurement-based explanations over the fluffy audiophile jargon and snake oil sellers. So, you fit me well, although I acknowledge there are other approaches in this forum. I enjoy reading you guys. Thanks!

Ps: I will continue experimenting with my speakers and room as soon as i can get rid of the 7 teenagers that stormed into it this morning to play MTG, D&D and eat pizza while playing music in my imperfect system, sitting at a totally suboptimal location.

 

[dominikz]

I bow to you @dominikz . Simply outstanding responses. Full of content yet concise and understandable.
I can't thank you enough for taking so much time, even built a model of my room! And being so pedagogical and kind. Truly appreciate .

Thanks a lot for the kind words - made my day!
IMHO we all benefit from sharing knowledge with each other. It is both a resposibility and a privilege to be in a position to do so.

Ps: I will continue experimenting with my speakers and room as soon as i can get rid of the 7 teenagers that stormed into it this morning to play MTG, D&D and eat pizza while playing music in my imperfect system, sitting at a totally suboptimal location.

I somehow suspect that they managed to have fun despite the nulls in the bass response of the left speaker