Room Treatment? How important is it to treat the wall behind/between the speakers?

PS. No clue how good it is but T+A has an EQ module and room correction software. The module is $3200 + installation and there is an authorized service center not too far from me.   

In the meantime I can use the corrected frequency response filter from DIRAC to the streamer. Corrected screen shot now in my profile/VS.

@gournard  Thanks for adding your ideas for the OP’s benefit. To answer your question, I use OmniMic V2 (V5.2 compiled on 2020-04-02) which is not the newest version.  I need to do my due diligence and look at the new version to see what is better and if I need it (e.g. I do not design speakers).

@macg19  It’s best to take measurements from your main listening position.  So, can you buy a longer cord to the mic from your laptop and/or DAC to take measurements from the MLP, or can the stereo components be pushed closer to the MLP to accommodate the mic being where your head would normally be?  To capture more of the room effects point the mic vertically towards the ceiling.

On a different note, I’m sure T+A makes amazing gear but I might suggest that $3.2k can be used elsewhere for greater effect rather than just for EQ which your DIRAC will already do (or am I missing something?).  You can’t DSP/EQ yourself to better early reflection symmetry or shorter bass decay times (the last time I checked). 

Regarding your 2" thick panels for the right side bay window and curtains that are in front of the panels, these absorb the highs and some of the midrange, but the windows themselves act as bass traps, so for early reflection symmetry reasons, your left sidewall will need to acoustically mimic what’s going on with the right sidewall’s 1st order reflections which looks like broad spectrum absorption.  I’d suggest replacing the left sidewall’s wooden slot treatment with a 6" thick absorption panel (e.g. GIK Monster panel) with an air space up  to 6" for the Left speaker->Left_sidewall bounce as a starter.  For your ceiling try 6" deep Skyline diffusers made from styrofoam (so that if it ever fell it wouldn’t impale you) for the 1st order reflection points.

@kevinzoe 

You can’t DSP/EQ yourself to better early reflection symmetry or shorter bass decay times (the last time I checked). 

Agreed. 

Styrofoam diffusers  - like this one?

Agree with moving the speakers farther away from the rear wall. Also move the side panels further up each side wall. 

Looking again at the system I see that you really arent dealing with many first reflections due to the placement of the double panels. These panels need to be placed farther in front of each speaker for first reflection. Difficult on the side which has the curtain. So if you bring the speakers into the room another 2 feet, the side panels should be another 4 to 5 feet in front of the speakers on the side walls.