@Lorenzo_Mutti I had a look at your measurements.
First I have an issue with the recorded SPL level which is >120dB, obviously the calibration is wrong, otherwise you are probably deaf by now Have you properly applied the calibration file of your microphone? Or have you inadvertently used the onboard microphone of your computer (happens to me often…)?
Provided your recordings are good at least in relative terms, and looking at the bass mainly, here are my findings:
You actually have a dip on the left side 50Hz to 70Hz. It’s not too bad in my view as there is no dip in this range from the right speaker. The only way to limit the dip is to change your speaker placement or listening position, or your room .
Your room is way too reverberant for high-end hi-fi. Only passive treatment can address this. Start with bass traps with large bandwidth to cover up to the low mids. You won’t be able to lower RT60 to 0.4 starting from that high, but at least try to reach a somehow flat RT60. Please not that RT60 here is what is seen in the “overlay” tab of REW, which is by default Topt, roughly 50% of the RT60 as defined in the litterature.
ETC is not bad at all, always good if you can absorb first reflections a bit more.
You have some important modal peaks before and after 100Hz. Bass traps will help here but in the meantime a little EQ can improve your listening experience. I quickly built a stereo correction file with REW EQ. Note that the filters are very different from Left to Right.
The associated stereo impulse response is here and can be loaded into Roon convolution engine in a few clicks. The master data file is here, including time aligned averaged L and R responses.